Donald Trump’s combative campaign manager, Corey Lewandowski, is working on a book, according to two sources with knowledge of the project.

The book, described by one source as “How Trump Did It,” would offer an insider’s account of the billionaire’s unconventional, and expectation-defying presidential bid. The source said several imprints have expressed interest in the project, though it’s unclear whether Lewandowski is actually shopping an official proposal yet.

A second source told BuzzFeed News that Lewandowski has reached out to a potential ghostwriter.