***, the symbol was called.

When *** was handwritten on books and periodicals in the New York Public Library’s permanent collection, it meant one thing: supervision required.

The triple-star code, created some time in the first part of the 20th century, identified the printed works that were considered too hot for the general reader to handle.

Playboy was once classified with a triple star. So were raunchy pulp novels, fliers for Times Square massage parlors, business cards offering phone sex for $2 a minute, even playing cards with illustrations of naked women.