Joe Moscheo spent time with Elvis both professionally and as a friend. As a member of The Imperials Moscheo sang backup to Elvis for four years. With that you might expect some more insight than what is given here. In The Gospel Side of Elvis Moscheo gives a fairly sanitized view of the King. We should really expect that since Priscilla Presley wrote the foreward to the book.
Moscheo may be a good singer but he is not a writer and this book could have been much better had the publisher employed a ghost writer and maybe a better editor. The writing style comes off amatuerish and repetitive at times. We hear over and over about Elvis gathering folks around a piano and singing gospel songs after his concerts. Interesting but why did he do this? We learn a bit about Elvis's upbringing and how maybe that influenced him but as far as delving deeply into Elvis's interest in gospel music this is lacking. The gospel albums he issued are very briefly discussed but Moscheo should have researched the recording of them and what went in to them and why certain songs were recorded. Elvis won his Grammy awards for his gospel music but this was just glossed over rather than any in depth research done as to why.
While those with an interest in everything Elvis will want to read this account from a person with up close ties those who want more answers will need to wait for a more authoritative work to come out on the subject. In the mean time anyone interested hearing the gospel music of Elvis should start with Amazing Grace His Greatest Sacred Performances.