I got 'Yeast' first, and got a lot of great information and practical advice from it. I use it as a reference book all the time.
I got 'Hops' next and was somewhat disappointed. It really doesn't tell you anything technical. Nothing that I find I can use everyday. I've read it a couple of times, and it seems to leave me more confused rather than answer questions. A lot of it is how different breweries use their hops, and a lot of that advice is contradictory. Yes, it has a lot of information on hops, but I was not impressed by it. If I'm after some information on hops, or how to use them, I usually either google it or search this forum, and do my own research, rather than pull out the book.
Because of my impression on 'Hops', I never got 'Water'.
I didn't know there was a 'Malt'. I think I'll have to invest in that one. I'd be interested in what people think about it, and how it compares to the others.