The thesis of German historian Detlef Garbe on JW in the Third Reich now becomes also available in English. To me this is still the best in-depth analysis of the JW history in Nazi-Germany. Despite the Watchtower's attempt to exploit him he remained neutral and also made some critical notes at Stand Firm-exhibitions. In some cases, Garbe has a different point of view as Penton who is more anti-Watchtower.
Paperback:
http://www.amazon.com/Between-Resistance-Martyrdom-Jehovahs-Witnesses/dp/0299207943/ref=ed_oe_p
Hardcover:
http://www.amazon.com/Between-Resistance-Martyrdom-Jehovahs-Witnesses/dp/0299207900/ref=ed_oe_h