The Pink Triangle: THE NAZI WAR AGAINST HOMOSEXUALS by Richard Plant (New Republic/Henry Holt: $19.95; 257 pp.)

In the concentration camps, the Nazis first dehumanized the inmates. They shaved all body hair, dressed them in uniform and tattooed them with numbers. As sole distinguishing marks, prisoners wore colored badges to denote the nature of their so-called crimes.

The red triangle was for political prisoners, green for habitual criminals, blue for would-be emigrants, purple for Jehovah’s Witnesses, black for vagrants or Gypsies, and the pink triangle for homosexuals. Jews wore a yellow triangle superimposed by one of the above colors to form a star of David.

The Nazis’ racial theories condemned anyone deviating from the Aryan ideal as “contragenic.” Their homophobia, like their anti-Semitism, rested on centuries of superstitious hatred. The moral tolerance of the Weimar Republic made the gay community a visible scapegoat for the defeat of Prussian militarism.

Heinrich Himmler, who ran the SS and the camps, became obsessed with the idea that homosexuality was an infectious disease, endangering the “National Sexual Budget.” Gays were “propagation blanks” in the agenda for increasing the master race.

Although homosexuals constituted one of the smallest categories in the camps, the SS brutalized them with a special ferocity. Few survived the beatings, the infamous quarries (dramatized in Martin Sherman’s play, “Bent”), castration and ghastly experiments to make them “normal”; others became sexual slaves to the guards and kapos .

When liberation came to other inmates in 1945, many homosexuals remained in jail to serve out the rest of their sentence. West Germany did not abolish Paragraph 175 of the Nazi Penal Code, under which gays were persecuted, until 1969.

This might explain why we still know comparatively little about the Nazi war against male homosexuals. Author Richard Plant, who escaped Germany in 1933, began his exploration during a personal search for lost friends. He went through a vast quantity of confusing and fading records, and he tried to interview survivors who would rather not talk.

The result is a book that contains much generalized research with too little about individual fates. While Himmler and Ernst Roehm are given full psychological profiles, their victims remain nameless statistics. Only in the brief prologue and epilogue do we glimpse the personal anguish involved.