I've binged through 'The Luna Trials' and can tell you straight up: it's a trilogy — three books in the main series. The way the plot is structured really leans into that three-act vibe, so each book feels like its own rising stakes, payoff, and then setup for the next act. If you want the simplest takeaway, the core story wraps across three volumes.
Beyond the bare count, I love how each installment expands the world slowly; the first book hooks you with the central mystery, the second widens the consequences, and the third goes for the emotional and plot payoff. There are also a few interviews and bonus short pieces the author has shared online that add flavor, but they don't change the official book count. For me, reading the whole trilogy in a week was totally worth it — it's tight, satisfying, and the characters stick with me.