I've read part one and have only just gotten my hands on part two, but Ken Ellis' "Testing to the Limits" deserves a mention if you ask me:
Testing to the Limits: British Test Pilots Since 1910 - volume 1, Addicott to Humble
Testing to the Limits: British Test Pilots Since 1910 - volume 2, James to Zurakowski
This seems to be the first book (or rather books) to cover the many test pilots that supported the British aviation industry. It includes short (and some longer) biographies of all mentioned pilots but also a few longer articles about the changing role of the test pilot throughout the years. Ellis has included all the pilots who either performed the first flight on a type or who gave their lives in the course of their work. That obviously means that not everyone is included, many production test pilots had to be left out for example, but this is still a very comprehensive book. It is also extensively illustrated to show the many different types flown throughout the years.