Based on an aside in Mahatma Gandhi's autobiography, in which he mentions a brief but seductive youthful flirtation with an Englishwoman, The Woman Who Knew Gandhi boldly imagines a long correspondence between a spiritual leader from the East and an ordinary woman from the West. In 1948, just after Gandhi's assassination, Martha Houghton receives a letter from Gandhi's son, who himself lies dying of tuberculosis in Bombay. Having found a stash...