For all german speaking (or reading, of course) pilots i can suggest:
"Der Spaßpilot", written by Harry Grunewald.
Der Spaßpilot: Ein Fliegerleben als Pilot bei der Bundeswehr: Amazon.de: Harry Grunewald: Bücher
Harry was a pilot within German Armed Forces and has written this book after his retirement from the army.
He writes down all his flying adventures-from helicopter basic training to his last flight in a helicopter..
Unfortunately it is only available in German....
I will try to contact him and see if he is going to have it translated into english some day...
I am looking for books about commercial helicopter operations in the 1990´s - 2010´s.....or about books from pilots like the "Ass monkeys" (Blackwater Aviation-Presidential Airways in Iraq/Afghanistan)...
Any suggestions?