Patrick,
My personal preference is to find books written by the architects themselves in their words. Secondly, architects writing about other architects.
The one exception I would make would be to first suggest Geoff Shackelford's terrific, "Grounds for Golf." It is quite possibly the best primer on GCA ever. I wish I had written this book. Among other things, especially for those who like visual cues, he lays out very well the different schools of architecture, by taking a single hole and showing how a designer from each school might design that hole. It's a solid place to start.
My list would be very similar to Robert Ball's.
To that list I would add:
"Golf has Never Failed Me," Donald Ross
"The Course Beautiful," A.W. Tillinghast
"The World Atlas of Golf," various authors (the section on the golden age is worth the price of admission)
Any of James W. Finegan's fine books. Though not strictly about golf architecture, and sometimes more like a travel book, his writing is very good and immensely pleasurable, while providing wonderful detail on the courses he covers.