Marquardt says in his conclusion:
" I conclude that the overwhelming evidence shows that Joseph Smith used the Book of Breathings (Joseph Smith Papyrus XI, col. 1) and considered it the writing of Abraham. The fact is that the papyrus which he used as the source of the Book of Abraham manuscript characters has nothing to do with Abraham. It is an Egyptian record which gives directions for wrapping up the Book of Breathings with the mummy. The papyrus roll that Joseph Smith used for his Book of Abraham was written for a man named Hor, a priest of Amon-Ra, who died about A.D. 60 far from the time of Abraham."
Apart from the Creation account that was paraphrased from Genesis 1 and 2, the rest of the Book of Abraham is not the translation from the papyrus as claimed by Joseph Smith; it is bogus. Joseph Smith could not translate Egyptian writings. That means that he could not translate the "reformed Egyptian" of the Book of Mormon either. He is a false prophet for claiming he could do so.
What is the Mormon response to such evidence? Several times Mormon missionaries have asked their bishops about this. The answer is not very satisfying. Like other cult groups, the meanings of words are changed. Contrary to the meaning of "translated", they mean spiritually transmitted or inspired. We expect that a translation reveals the true meanings of symbols and words of a different language. They say that by looking at the papyrus Joseph Smith, Jr., was inspired to write a paragraph for each symbol. Or a spiritual guide (fallen angel) put ideas into his brain. They admit that the Book of Abraham text and meaning have nothing to do with the Book of Breathings meanings in the papyrus. By such excuses they would be satisfied if someone looking at the papyrus had written a poem like "Mary had a Little Lamb" and claimed that such was a true translation of the writings on the papyrus.
Other evidence indicates that as a teenager and young adult Joseph Smith, Jr., was into occult practices in an effort to relieve his poverty. That left him vulnerable to influences of Satan and the fallen angels. There are several different accounts of what he saw in the woods at the time of his first vision. It is most likely that there was an "angel of light" as a disguise which deceived Smith. He was thereafter fed corrupted information from such fallen angels. This appears similar to the appearance of the angel to Mohammed centuries earlier. There are several parallels in the lives of Smith and Mohammed in the years after their encounters with the "angel".
Ultimately, we should put no trust in the works of Joseph Smith, Jr. Of course, some of his writings are the Word of God - those taken from the Bible. The rest are from his own imagination or fed to him from the wrong angels. We should put our trust instead in the Bible and the finished work of the real Jesus Christ.
Book of Abraham,
Intro, Book of Abraham, Creation, Origin, Papyrus, Meanings, Facsimile-1, Facsimile-2, Facsimile-3, other errors, summary