Yeast: Great book that covers everything yeast related. If you plan to run a miniature yeast lab this is the first book I would recommend. Even if you still use pre-packaged yeast it has a lot to offer in terms of discussing yeast health and fermentation. It's not a light read and I would say that more experienced you are in homebrewing the more practical use you will get out of the book.
Water: Easily the most overwhelming of the series. This book talks about everything from waste water treatment to in-depth chemistry. It is probably more detailed than an actual water plant manual, and it actually walks you through quite a few operating water plants at various breweries. I wouldn't say this is a book about water adjustment, it literally is "all things water."
Hops: I feel this has the greatest entertainment value, so even if you aren't interested in the science of hops there is still something to be gained from reading this book. You will get a lot of data and charts displaying information about flavor compounds in hops, bitter compounds, acid percentages, etc. There is information on the history of hops, the parts of the plant, hop production numbers, information on growers, hop selection, etc. What I really like about the book is that circling all of this data is the Stan Hieronymus method of storytelling which keeps me reading the book. I honestly found it more interesting to read the stories than all of the data in the book:
"The museum sill keeps a straw hop devil on display. Farmers feared the gusty winds and thunderstorms that could destroy a hop yard in the final days before harvest and hung the large straw figures in their fields to ward off bad weather." ~Stan Hieronymus: For the Love of Hops