Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
Third Person (Limited Omniscient)
James's use of point of view is one thing—the main thing, even—that makes What Maisie Knew a big deal.
It's probably the reason this book is famous, so you'll want to pay attention to how James's narrative perspective stays close to Maisie's limited perspective on every page. After James's preface, which fills readers in on backstory in an omniscient way, we're right there with Maisie until the end.
James uses limited omniscient narration to bring her experience home to us and help us understand her. A bitter divorce is "confounding to a young intelligence" (I.1), and so it is to our consciousness as readers who are with Maisie in the dark, only gradually able to make sense of what's happening around her.