Joseph Smith claimed to have "translated" the Book of Abraham from Egyptian papyra acquired from a traveling vendor displaying mummies. The LDS Church now contradicts it original claim that the text found in the papyra and purported to have been "translated" by Joseph Smith was originally written by Abraham's own hand. Until relatively recently, that same claim was found in the published preface to the Book of Abraham found in the Pearl of Great Price.
The claims of the LDS Church on the subject of the Book of Abraham, including the claim that the document was translated; the claim that it was written by Abraham; and the purported content of the translation, have been completely, conclusively, categorically, and irrefutably discredited by modern scholars.
Egyptologists have examined the same papyra and found it to be a standard funerary document having nothing whatsoever to do with Joseph Smith's purported translation.
(Featured fair use video clip is from The Lost Book of Abraham masterfully produced by Institute for Religious Research (irr.org) in cooperation with Grooters Productions. Full video is found here.)
Completely unmotivated independent scholars who have no axe whatsoever to grind against the LDS Church or Joseph Smith have referred to Joseph Smith's translation as an "impudent fraud".
Does the indisputably established "impudent fraud" of the Book of Abraham give rise to fair and reasonable questions about its authenticity and about the legitimacy of the claims of divine authority or inspiration of those who continue to profess the truth of the book?