The author, historian and sociologist H. G. Adler (1910–1988) was a member of the first post-World-War-Two generation of Jewish scholars to subject both the catastrophe suffered by the European Jews and the Nazi system of human annihilation to comprehensive analysis. The achievements of this generation of scholars have largely been forgotten in contemporary academia. Of Adler’s main historical works, only his book on the coerced community of the Theresienstadt concentration camp is currently in print. The article pays tribute to this book, reviews its genesis and publication history, and underscores insights formulated by Adler that retain their validity to this day. Adler’s relationship to Adorno is examined by way of their correspondence, the use Hannah Arendt made of Adler’s research in her report on the Eichmann trial is critically assessed, and attention is drawn to Adler’s efforts to educate the German public on the genocide of the Jews.