I would venture to suggest that the Schweitzer book, ground-breaking in its time, is now of historical interest only, Jesus scholarship having moved on so much in the century-plus since it was written. You may as well throw in Renan's (far older) Vie de Jesus. As Rhi said, Geza Vermes is the kiddy.
I think that's a bit unfair on the Schweitzer book, particularly since you suggest it's in the same order of relevance as Renan's Vie de Jesus. After all, it's the starting point for the researches of Bart D. Ehrman, who seems to be here to stay, even though I wouldn't rate him alongside Vermes.
In fact, all these above thinkers follow Schweitzer's lead in suggesting that Jesus was a 'failed Messiah' who did not see the God imminently intervening in history to establish his Kingdom as Jesus had supposed. (That of course did not prevent Schweitzer from seeing Jesus as a major inspiration in his life). The idea of Schweitzer's that is particularly outdated is his insistence on the priority of Matthew among the synoptics, and I have to say I find that extraordinary.
However, the book has further importance in that it was in itself the result of Schweitzer's extensive reading of objective biblical research from its origins in the fear-ridden speculations of Samuel Reimarus up to Schweitzer's own time (as is evident in its original title "From Reimarus to Wrede".
