theory11 — Magic Tricks & the World's Finest Playing Cards

Are these books any good?

I have expert card technique. Id say its pretty good. Its got alot of stuff in there. I dont think it does very well in the way of teaching though. I have a hard time learning card stuff from books though. If you want something with a little bit of everything I would recommend it. Plan on reading sections over and over and over, both with cards in hand and without.
 
I've heard nothing but great things about Expert Card Technique. Hugard, Braue, and Buckley are all extremely credible names in card magic, and not without reason. I personally own Card Control, and I'm going to warn you now that I would put it in the same general category as Erdnase's classic Expert at the Card Table in terms of being a very small book full of extremely difficult moves.

They're both definitely worthwhile investments and I'm sure you'll get a lot of use out of them.