I read this pamphlet after having visited the B-39 "Cobra" moored at the San Diego Maritime Museum: it is basically the same booklet as "RUSSIAN SCORPION: FOXTROT-CLASS SUBMARINE" (which describes the B-427 "Scorpion" berthed alongside the Queen Mary, not far away in Long Beach) but with more generic information, including an excellent section on how to dive and surface the submarine not found in the Scorpion's pamphlet.The B-39 isn't in as good shape as the B-427 since it was mothballed, and hence scavenged from, before it found its way to San Diego: nevertheless, either version of the Jasper Communications pamphlet is an excellent guidebook to the historically important Foxtrot (Project 641) class of Soviet diesel boat.