Cornell University Press published a serious book of history about the Grateful Dead: Cornell '77: The Music, the Myth, and the Magnificence of the Grateful Dead's Concert at Barton Hall
The concert in question was just one show in the band's 1977 spring tour; it happened to be on the campus of Cornell University and was organized by the students at the university.
I'm sure you have to already be a fan of the band (a "Deadhead") to really enjoy the book; certainly you have to be at least a little interested in the band to have any interest in the book.
I really liked the book and passed it on to my brother-in-law, who is also a Deadhead, and who even has a collection of CD's of recordings of other concerts on the same tour.
My guess is that: if you're a little bit interested in the band but not very knowledgeable about them, you'll learn a lot from Cornell '77, while if you're already very knowledgeable about the band, you won't learn very much. I guess I was somewhat in the middle, because I learned more than I was expecting to learn (including a little bit about Cornell University, about which I knew next-to-nothing).