For 3-finger/bluegrass style, one other really highly recommended book is You Can Teach Yourself Banjo by Janet Davis (Mel Bay). Despite the title, it's good to work through with a teacher as well as on your own.
I also like Roy Clark's Bluegrass Banjo Bible. These two books make a nice pair for getting started.
Of course, the Earl Scruggs book is great, but a little tougher to parse, maybe too much info for some beginners.
Also, as noted above, the online banjo community is an amazing resource.
Good luck!