I think the root of the misunderstand in this situation is what type of Apostasy was present after the maryterdom of the Apostles. We both know that the Apostles were ultimately regected and many suffered a myarters death, with the sole exception of the Apostle John the Devine who wrote the Book of Revelations.  
 
At the death of the Apostleship and the rejection of there leadership of the Church of Christ, there was a Great Apostasy. This was not a total apostasy for if there was a total apostasy there would of been no ability for a restoration to happen at all since a total apostasy would me nothing survied of the Church Christ set up.  
 
What we mean by the Great Apostasy is that the priesthood authority and the keys of the kingdom that Christ gave to the Apostel (and First President of the Church) Simon Peter were lost from the Earth with his death and rejection.  
 
This did not mean hell prevailed against the Church since the Church is founded on Christ (who is the cornerstone) and hell has no power over Christ. What it does mean though is man's ability to seal in heaven as well on Earth which is required to perform the ordiaces of salvation was lost.  
 
Now without the keys of the kingdom mankind did go on and did it's best to preserve what it had before this loss of authority. Without the contributions of the Catholic Church there would be no Bible (though they did fight tooth and nail too keep the Gospel out of the hands of the people for centuries), with no Bible there is no Restoration since the Prophet Joseph Smith would never of had access to James 1:5 which inspired him to inquire of God himself which Church was the true Chruch.  
 
You are right there is some doctrine in the Church of Jesus Christ of Latter-day Saints that we do not find in the Holy Bible, which for some could be a problem. Given though that there is only 4 out of almost 36 gospels recorded in the Bible (the rest either under lock and key of the Vatican or destroyed by Papel order) I do not see a problem with this. It is either likely these teachings were present but not allowed into the Holy Bible by the Cartheginian Conventions or that they were destroyed before the man voted on the Bible anyway.  
 
Even if there is no teachings present (which is not the case) there still is not hole in our doctrine. There was no doctrine of Baptism before John the Baptist. There was no doctrine of confession before Christ, on top of that Christ ended the doctrine of animal sacrifice, also Peter ended the doctrine of circumcision.  
 
The prophets recieve Christ's will and do change doctrine as we become more mature and understand Heavenly Father's plan better. The Bible records changed to the coveanat between man and Heavenly Father if it was done before as we became more enlightened why can it not happen in 1830? 
 
Also there is a lot of Biblical references to modern doctrine of the Church. Baptism for the Dead (1Corinthians 15:29), Multiple Kingdoms in Heaven (1Corinthians 15:40-42, John 14:2, 2 Corintians 12:2), Man's ability to become like Heavenly Father (Psalms 82:6, Romans 8:17)  
 
The Chruch has no doctrine of the existance of any other God besided the Father, the Son, and the Holy Ghost who are three beings united in purpose. 
 
Touching on the subject of eternal progression, while I cannot recall any specific bible passages off the top of my head I know for fact that LDS are not alone in this beleif that we still progress and learn beyond this life, I presbytarians and most of prostestantism hold various beliefs of progresing and learning beyond this life. 
 
You also asked why does the LDS Chruch use the Holy Bible if it came decades later, why would we not accept the Holy Bible as far as the translations are correct. While the Bible is not free of error it is still the largest and the foundation of the doctrine of the LDS Chruch. Without the Bible there is no LDS Chruch, the Bible is the source of the restoration and while we know it is not inerrant we still recieve much joy and spiritual knowledge from reading it's precepts. We accept the King James Version of the Bible, as an autoriative source of doctrine. The great thing about the coming forth of the Book of Mormon is the two Books reinforce the comandments and doctrine of Jesus Christ to mankind and eliminate the multiple interpretations you see in the rest of Christondom.

I love that you are so ready to talk about theology - you are the one who answered another question of mine several months ago. Now I don't expect to change your mind on most things, but I would like to at least clarify some Catholic positions that you mentioned here. 
We believe public revelation ended with the death of the last apostle - not because God no longer guides us (that's why he set up a church that he promised to guide into all truth) but because with Jesus, the Word of God, God had spoken his final word. We believe the church's role, then, in revelation, is to guard the deposit of truth.  
I have to say about fighting tooth and nail against letting the people have the Gospel, please think about that. I have heard the accusations - the church chained the bibles down, wouldn't let it be printed in the vernacular, etc....But think! If the monks had not copied the Bible by hand, laborioiusly, word by word, with beautiful illustrations,etc...the Bible wouldn't have been passed down. Were they chained? sometimes, at least, absolutely! As were books in libraries. After all, when they were so costly, they had to be protected so that people COULD have access. All in Latin? Not true, but for the most part yes, because that way there was a universal language that everyone who was educated could understand. Remember that this was before the printing press, so who could read? Only the wealthy and the clergy and the people they taught. Churches of that time are like the gospel in stone - the statues, the stained glass, etc..pointing to heaven and telling the stories. Nothing could be further from the truth than that the Catholic church tried to keep the Bible from people. 
I would encourage you to read the church fathers, those men who knew the apostles, or the disciples of the apostles, and see for yourself what they believed. There are volumes of their words still left. It's fascinating to see the parade of heresies - and how they were countered, like a shepherd using his crook to keep his sheep away from danger.  
And then ask yourself again - if these men who, guided by the Holy Spirit, chose this group of books we call the Bible, but they also taught so plainly that there is only one God, infant baptism, original sin, the primacy of the bishop of Rome, etc...then they couldn't have been Mormon, and why are you following them on this one thing only?

While I respect your positon I disgree that God will ever make an end to his dealings with man as long as men still draw breath.  
 
"Jesus Christ the same yesterday, and to day, and for ever." (Hebrew 13:8)  
 
"Surely the Lord God will do nothing, but he revealeth his secret unto his servants the prophets." (Amos 3:7) 
 
The Holy Bible makes a strong statement (backed up by the Book of Mormon that God will always speak to his prophets and Apostles. I could almost believe your posotion if the Apostleship never ordained Mathais, Barnabus, and Paul. Why ordain additonal members to fill vacancies in the Quorum of the Twelve Apostles if they were not suppost to be here to lead the Church?  
 
I fail to see Christ giving them the Keys and not expecting there leadership to stand. There loss was no in accordance with Christ's desires, but man has the free will to do as he pleases even if his actions go against the plan of the Lord.  
 
As far as the statement that the Catholic Church has never attempted to keep the Holy Bible out of the publics hands, tell that to those who were burned at the stake for translating the Bible from Latin.  
 
Murdering people for maknig the Holy Bible more accessable to the public is not helping, the Church activly killed scholars who dared to try and translate teh Bible until the Protestant Reformation nearly ended the Roman Catholic Church and forced them to end many of there questionable practices like tourcer, murder, and Indulgences

I don't believe that God doesn't interact with man, just that He doesn't keep changing His mind on doctrines (look at the LDS changing position on aborton, for example - I'm sure most Mormons are personally against it, but the church itself does make many exceptions for it, while still maintaining that the fetus is a human life). He does guide us through the church. And you're right that it is very important to recognize that there was succession in the church, so that we could follow St. Paul's stricture to hand down all that had been taught, both oral and written.  
(See 2 Thessalonians 2:15 or 2 Timothy 2:2, for example). We call those men bishops rather than Apostles.  
"Jesus Christ the same yesterday, and today, and forever" Amen! But I never understood why Mormons put such emphasis on it when they believe in such changeable gods. If men can change forever, why is Jesus alone static? Perhaps he's unchangeable from now on, but how did he get that way ? He couldn't have been the same "yesterday." 
The church did translate the Bible into some of the vernacular languages before the Reformation, but I'm sure it did burn others, as I would not hesitate to burn a Jehovah's Witness, error-filled "translation," and for the same reason. Has there ever been torture and death over religion? Sadly, yes, but it's certainly not one-sided - did England, for example, just happen to become almost 100% Protestant because of personal beliefs, or because the monasteries were emptied, priests drawn and quartered, etc, esp. under Elizabeth....? But we don't reject Peter because of Judas. 
Enjoying the discussion - hope you are too

I think that doctrine do cahnge and I do not see how one thinks that it doesn't if they read the New Testament.  
 
The doctrine of circumcision changed (and caused an uproar amung many of the Jewish memebers of the Ancient Church) and the doctrine of Animal Sacrifice was changed when Christ fulfilled that Law.  
 
Also look at how the doctinres about homosexualtiy, adultery, honroing your parents have all changed.  
 
Before if you commited one of the above mentioned crimes you were stoned to death. Now the only punishment is excommuniocation and the knowledge of the consequecnes at judgement day should one not repent of there sins.  
 
The doctrine has changed as be grow spiritually and become more mature and ready for more revelation and enlightenment. As we become more like Christ as a Church we learn to be like Christ and to forgive the sinner instead of condemn them. Which is why doctrine will change because we are becoming more like Christ and less like the flesh. While the eternal principals behind the doctrine will never change, doctrine is man's interpretation of God's will and men change hence the interpretation will change to become more in line with Christ's nature instead of our nature.  
 
I too agree that Christ is the same yesterday, today, and forever. I also agree that man changes ever second, and Christ give us additonal doctrine and gudiance as we are ready for it to come to us. This is the way it has been since the Garden, the only thing that would make Christ and Heavenly Father chagne is if the new doctrine and revelations stopped like the mainstream of Christianinty procliams it did.  
 
Trying to excuse the killing spree of the Catholic Chruch in there thousand year reign of terror in the dark ages by sayign that the reformationists also attacked catholics is poor. While retribution is not the way of Christ, one cannot be blamed for wanting to reveng the horrible acts commited against them by the Papacy in there power hungry (and unrepentant) murders of tens of thousands of men, women, and children.  
 
Also the Bible clearly defines the differences between a Apostle and a Bishop, a Bishop is not the same as an Apostle. A bishop presides over a congregation not the entire Chruch and Apostle is the only office ever authorized by Christ to preside over his Chruch in his absence.  
 
The is the key arguement of the Chruch of Jesus Christ of Latter-day Saints, there was no one to cary the leadership of the Chruch after Peter. The world rejected Christ and killed his leaders, no leaders means no priesthood authority.

Okay, what I mean when I say doctrine is a moral teaching, one that doesn't change. Many of the things you mention are what I would call 'disciplines.' As you say, of course they change. For example, the stoning or the circumcision were disciplines, but what has not changed is that adultery is wrong and that children need to be brought into covenant with God (now through baptism). I should have been clearer because the LDS church uses many terms we use but they often mean different things. (eternal, sacrament, priesthood, for example) 
 
Now, as to the original question about the apostasy: looking at your last paragraph, may I understand that it is the LDS postition that the true church all but disappeared with the death of the original apostles? Then I ask again, how? That time period is not actually a blur of history, with no written records. There are volumes of books with records of the controversies raging. Some challenged the idea that Jesus was God, others that Mary was ever-virgin, there were many debates about the exact nature of Jesus, and on and on. If the Catholics wished to "whitewash" it all, why leave those records? But it did, and we can see who brought up and argued for the heresies, who defended against them, and how they based their arguments on Scripture and the teachings of the Apostles, sometimes being martyred for these truths. It's just really hard to believe that a church Jesus founded, that He promised would be guided into all truth, that he left as a final authority (see Matthew 18) would disappear without a whimper from the world stage, leaving humans floundering around as without truth as before He came.  
 
And again, if you do believe that, then these men calling themselves the Catholic Church from AD106 onward who taught infant Baptism, the Real Presence of the Eucharist, 7 sacraments, and on and on, had to be a false church, yet you use their holy books as the Bible. That would be like me rejecting reincarnation, the caste system, multiple gods and everything else about Hinduism yet clutching to the Vedas as holy words. 
 
I know you disagree with me, but I look forward to your response.