In this book Dr. Kahn shows himself as a deliberate wit in a field not yet professionally acknowledged as humorous. Warning us of the dissipations that interfere with study he condenses complexes to a compact ninety, of which 'Homo Sexual' is number 52 and Sex is 17a subheaded under Ancestors, 17… He quotes wise men of all ages, amending their statements when they fail his purpose, and adroitly avoids getting serious by never implying that it could be fun to study.