John Dehlin has posted a 2 1/2 hour video dedicated to gushing over Grant Palmer. Sadly, Palmer is dying of cancer; what is even sadder is that both he and Dehlin are unrepentant liars and, when they die (unless they repent), they will go to hell (see Rev 21:8; D&C 63:17).
To show the many problems of Palmer's "research" as found in his An Insider's View of Mormon Origins (Salt Lake City: Signature Books, 2002), one should pursue the following reviews:
Steven C. Harper, Trustworthy History?
Louis Midgley, Prying into Palmer
Mark Ashurst-McGee, A One-Sided View of Mormon Origins
James B. Allen, Asked and Answered: A Response to Grant H. Palmer
Kevin M. Christensen has a pretty good review of Palmer’s book on amazon entitled A False Balance.
Update: Palmer passed away on 25th September 2017.