I can't emphasize this enough, if someone is publishing a non fiction non memoir book that wasn't published by a university press you should examine it extra closely.
Why? First, because there's plenty of shit published by university presses that should never have been published--and university presses, in theory, have many people deciding if it meets the accuracy requirements for publication.
A non university press book, or trade press, book, *might* only care about sales. 1/3