This first volume explores Elvis's youth, up until age 24, when he was inducted into the army. Guralnick is a respected cultural historian, and this two-volume work is the definitive Elvis biography.
This second volume picks up where Last Train to Memphis leaves off and follows Presley through his death in 1977. Again, this two-volume work is the definitive biography.
If you are interested more in the "inside" story from a person with a unique attachment to Presley, you might like this older book from his young bride.