Nearly always, if I have the opportunity. Example: I've seen a few books by Lesley Blanch and have The Sabres of Paradise in a pile upstairs. Contemporary of Barbara Cartland writing about a 19th century Islamic revolutionary and Victorian sexual bohemians. Seeing a book written in an over-the-top style about such very exotic subjects, you want to know straight off, how did she come to do that? and did she know what she was talking about? The Wikipedia page isn't that great but it does say who she hung out with, which explains something.

https://en.m.wikipedia.org/wiki/Lesley_Blanch

The Sabres of Paradise reads like a novel but the biography makes it clear that it wasn't one.