I bought a couple of copies of Gene Beggs book about ten years ago - gave one away and lent the other out never to have it returned.
I tracked Gene down via the IAC - gave him a call and ordered the books - he couldn't take credit cards but was happy with an International Money Order.
He was in his seventies then!
The Beggs/Muller or Muller/Beggs recovery for the Pitts certainly works and does so in some other aeroplanes but is not guaranteed to work in every craft.
It is quite disconcerting to enter a spin, let go of the stick, close the throttle (the latest tweak on the BM recovery is to use both hands to pull the throttle), press the higher rudder pedal then watch the stick mimic the inputs that you would have introduced!!
Never needed to use it for real but know it works in the S1 and S2.
ISTR that the Aussie CAA euivalent (DGAC?) had the POH of Oz Pitts' amended to show this recovery? Has dementia started early for me David P?
Stik