“Gloria Steinem: Her Passions, Politics, and Mystique,” by Sydney Ladensohn Stern. Birch Lane Press 288 pages. $24.95. This is Sydney Ladensohn Stern’s first foray into the biography genre.

Reading Stern’s book, anyone who grew up in the 1970s will recognize Etan Patz, the six-year-old boy who went for a two-block walk from which he never returned, not to mention that era’s total ...