Sokolow's Bluegrass book?

Hi all, I received a gift card for Christmas and want to spend it on some uke-books. I decided on Fred Sokolow 's Beatles book, as it seems to be about playing chordal melodies. Also, hearing some of the arrangements made me want to tackle these myself (even if some are in a different tuning).

That leaves room for an additional book, and I was thinking of getting the bluegrass book by the same author. Does anyone have it, and if so would they feel compelled to give their opinion / impressions about it? I am torn between either the bluegrass one, the ragtime one or the blues book. Uke is mainly for my own entertainment, so no particular need to learn any style for any sort of band or gig.