I own a hardcover US Army Center of Military History copy of this pamphlet, which was originally published as an internal study document for the US Army in the 1950s. This book was actually authored by George Blau, not Grant Gordon (the editor), and is based entirely on debriefings of Wehrmacht officers involved in the strategic and operational planning of operations in Russia from 1940 to 1942, plus some archival material they managed to retain. This book is definitely still worthwhile to obtain, although David Glantz's more recent works, with unprecedented access to Soviet archives and staff studies, has superseded this work. Nonetheless, it's still an excellent source of information that I return to often with the caveat that German generals post-war were keen to blame Hitler for German military failures, and the whole work must be viewed through that prism.