The theme which we have been tracing through James's major novels is that of innocence betrayed, but what of an innocence that is proof against betrayal? In the first of the novels to be written in James's late style, we encounter a heroine clad, like the Lady in Milton's Comus, in the ‘complete steel’ of natural virtue. Like Milton's Lady, this heroine is a little girl; at the start of her novel she is only six years old. What Maisie Knew is perhaps the most perfect of James's novels. It combines the lucidity and shimmer of a little French Impressionist painting with the complexity and logic of an algebraic expression. As the terms of the expression are cancelled out to give the only possible right answer, it transcends the idea of the happy ending.

In the preface to Maisie which he wrote for the New York edition, James relates the real-life anecdote from which the novel grew: