In the summer of 1934, "a sickly, pathetic marmoset" called Mitz came into the care of Leonard Woolf. He nursed her back to health and from then on was rarely seen without her on his shoulder. A ubiquitous presence in Bloomsbury society, Mitz moved with Leonard and Virginia Woolf and their circle, developing special relationships with such associates as T. S. Eliot and Vita Sackville-West. She accompanied the Woolfs on their travels and even played an important role in helping them to escape a close call with Nazis in Germany.

Using letters, diaries, and memoirs, Nunez reconstructs Mitz's life against the background of Bloomsbury in its twilight years. Tender, affectionate, and humorous, Mitz provides an intimate portrait of a most uncommon household, a glimpse of what Virginia Woolf once described as "the private side of life—the play side," represented by one's pets.