Popular Broadway musicals are often inspired by classic books.

For example, next month’s Spreckels Theater Company production of “The Curious Incident of the Dog in the Nighttime,” written by Mark Haddon and adapted for the stage by Simon Stephens. Kander and Ebb’s ‘Cabaret,’ opening August 31 at Cinnabar Theater, is based on John Van Druten’s play ‘I Am a Camera,’ which was based on Christopher Isherwood’s memoir “Goodbye, Berlin.” Then, of course, there’s virtually anything by Rogers and Hammerstein, who made careers from turning socially significant novels and memoirs into hit musicals.

Rarely does it happen the other way around, however, and yet that’s exactly the case with the Tony-winning musical “Dear Evan Hansen,” written for the stage by Benj Pasek and Justin Paul, and now novelized by actor-singer Val Emmich (’30 Rock,’ ‘The Big C,’ ‘Vinyl’). Marketed (logically) to a YA audience, ‘Dear Evan Hansen’ (the novel) was released last month, and the author has been diligently touring the country to promote it. But because he happens to know the creators of the musical (obviously, since they’re the ones who chose him to write the novel), Emmich has sometimes brought Park and Hall along with him.

Such will be the case in October, when Copperfield’s Books in Petaluma presents Emmich on stage at the Mystic Theatre, alongside the show creators, who will be performing songs from the musical. Tickets are $27, and include a general admission seat, a copy of the book, and a raffle ticket for a chance to meet the creators after the show.

Purchase tickets at Copperfield’s or online at CopperfieldsBooks.com.