Unschooled in the Game, I had never heard of the "Muzio gambit".
Wikipedia explains:

In the Muzio Gambit (like the similar Hamppe-Muzio gambit in a Vienna game), "white gives up a piece in the hope of establishing a powerful attack against the black kingside."

The Muzio Gambit serves a metaphor for our protagonist's battle to reveal the truth behind the sinister Mr. Chessman's manipulations.

From a discussion at chess.com:

    "The Muzio, while not really refuted, has lost much of its punch in this age of computers where defensive lines seem to appear magically out of nowhere. But it's quite a playable and exciting opening .... ... White gives up a full piece (two pieces in the Double Muzio) for tempo, development and an attack. Once you have invested that material, you crossed the Rubicon. You can not back down for a single move." ... "Of course, one must be tempermentally suited to play such an opening; it's not for everyone."