Pearl of Great Price (PGP) is a collection of scriptures of the Church of Jesus Christ of Latter-day Saints. The PGP includes: the Book of Abraham, a book dealing with Abraham's journeyings in Egypt, containing many distinctive Mormon doctrines such as eternal progression; the Book of Moses, a retelling of Genesis and Exodus; the Joseph Smith-History, a history of the early Mormon church by Joseph Smith; Joseph Smith-Matthew, a translation of the Gospel of Matthew by Joseph Smith; and the Articles of Faith, a brief summary of the major doctrines of the Mormon faith written by Joseph Smith for a newspaper.
Joseph Smith claimed he translated the books of Abraham and Moses from Egyptian papyri in his possession. At the time, scholars were not able to translate ancient Egyptian hieroglyphs, so the claim could be neither substantiated nor invalidated. However, the Rosetta Stone, which was found in 1799 but not successfully used in a translation until 1822 (see Jean-Francois Champollion) has allowed modern archaeologists to translate the papyri, showing that the original "source" text for the Book of Abraham is actually the "Book of Breathings", an Egyptian funerary text made for a man named Hor. It is a Pagan text consisting primarily of the names of Egyptian gods and goddesses.
(Church response to this finding, sympathetically worded, really needs to be included to be npov.)