In “The Secret History of Wonder Woman,” she fully tells Marston’s history for the first time, as well as the complete history of how so many crisp feminist ideas made their way into Wonder Woman comics. It’s complicated material that she capably explores, though she leaves you with uncomfortably torn feelings and a sense that this intellectual jigsaw puzzle is missing pieces. Should we read Marston’s Wonder Woman strips as feminist manifestoes, or as the working out of issues by a somewhat troubled man, or both? Her book makes you inwardly cheer, “Go Wonder Woman!” one moment, and then fret, “Go Wonder Woman?” in the next.

At Harvard, Marston was influenced by early feminists like Emmeline Pankhurst, who was prevented from speaking on campus in 1911. He’d later find Sanger’s books and ideas. After graduation, he married Sadie Elizabeth Holloway, an unconventional woman who worked as an editor for Encyclopaedia Britannica and other publications.

While teaching at Tufts, Marston met a student named Olive Byrne, who happened to be Sanger’s niece. Before long, he gave his wife an ultimatum: Either Olive lives with us, or the marriage is over. He had children with each woman. When prying strangers inquired about these living arrangements, he’d say that Olive was a sister-in-law.

Marston was slowly exiled from academia after being arrested on fraud charges in a business transaction, though the case never went to trial. His lie detector, based on blood pressure readings, never took off. He resorted to public relations stunts like calling his device the “Love Meter” and cuffing women to it while they watched romantic movies. Brunettes, he claimed to find, are more excitable than blondes.

He briefly worked as a psychological consultant for Universal Studios, and then in a similar job for Charlie Gaines, the publisher of Superman comics. Superman had arrived in 1938, and Batman a year later. The first Wonder Woman comic came out in 1941, and Marston was in the right place at the right time to create it, which he did under the pen name Charles Moulton. It was a hit from the start.

Image Jill Lepore Credit... Dari Michele

Ms. Lepore teases out Wonder Woman’s back story and explains how Marston put it together from previous literature. “She was an Amazon from an island of women who had lived apart from men since the time of ancient Greece,” she writes. “She came to the United States to fight for peace, justice and women’s rights. She had golden bracelets; she could stop bullets. She had a magic lasso; anyone she roped had to tell the truth. To hide her identity, she disguised herself as a secretary named Diana Prince; she worked for U.S. military intelligence. Her gods were female, and so were her curses. ‘Great Hera!’ she cried. ‘Suffering Sappho!’ ”