Wildfire mentions a few books in passing, but the most noticeable one is Icebreaker , Hannah Grace’s earlier Maple Hills novel, which is explicitly referenced as the author’s previous bestseller in the book’s description. The story itself is centered on Russ Callaghan and Aurora Roberts, two Maple Hills students who become camp counselors after a one-night stand, so the book reference is more of a series connection than a major plot point.
If you mean a book that appears inside the story as a character-specific read or a direct title mentioned in dialogue, the exact title isn’t clearly established in the available material.