All of the above - especially Testing Years and anything else by Roly Beamont. A quick scan of my nearest bookshelves also shows:
Test Pilot by Neville Duke
Janusz Zurakowski - Legend in the Skies, by Bill Zuk
Up in Harm's Way by Commander Mike Crosley DSC RN
Fly No More by Lt Commander Brian Davies AFC RN
Flying the Frontiers by Arthur Pearcy (NACA & NASA experimental aircraft)
Various biographies, including John Derry, Brian Trubshaw, 'Cats eyes' Cunningham, Geoffrey De Havilland and Harald Penrose
For a rather different aspect of test flying, try The Sky my Kingdom by Hanna Reitsch and Test Pilots by Wolfgang Spate. These have to be read to be believed, as they describe really 'off-the-wall' experimental flying in Germany in WW2
I think I have too many books... just don't start me on the space programme!