its a great read, but the quick price drop doesn’t bode well for publishing does it ?:(

It doesn’t help when the publisher then issues a superior hardback edition, which can also be had at discount prices.

Comet, for really good 1940s/’50s test-pilot books you can’t go wrong with Brian Rivas’ John Derry book which I would consider the master works reflecting that period and Derry’s story is just so remarkable.
Also Jeffrey Quills’ Spitfire: A Test Pilots Story, Neville Dukes’ Test Pilot, Mike Lithgows’ Mach One, Brian Trubshaws Test Pilot, and Peter Twiss’ Faster Than The Sun are very good straight from the horses mouth reads, all can be found cheaply on Amazon/EBay.
Good list here, http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Dstripbooks&field-keywords=test+pilot&x=7&y=26#

For a good oversight to all test piloting from early days to Tornado (some of the ’20s & 30s characters such as Summers and Cordes were very interesting), Test Pilots by Don Middleton is very good