In 1948, when Jane Fonda was 10 years old, she wrote a letter to her father, Henry Fonda, who was temporarily living in New York, performing on Broadway. The letter—accompanied by a drawing of butterflies—begins, “Dear Dad, I did not trace these drawings of butterflies.” Fonda, born Lady Jayne Seymour Fonda (she is distantly related to Henry VIII’s third wife), briefly mentions this anecdote in her 2005 memoir, My Life So Far, never returning to it, but letting its implication toll. “I was saying to him, ‘I have artistic ability,’” she tells me over Zoom one morning in February. “I could do it from my head.” Even from a young age, Fonda was spelling it out—laying claim to her inventiveness, her imagination, as if born with an urgency to make…