I'm probably gonna be an odd one out here with a cleaning book, but I really, really like K.C Davis's "How to Keep House While Drowning" book about cleaning your house while mentally unwell and not considering yourself a moral failure for the state your house is in.

I think it's the one that had the most amount of positive benefits to my life. It turns out having a positive influence in the form of a book that tries to encourage you take things one step at a time, a book that even admits it doesn't know everything either---well, it's more beneficial than my real life acquaintances and family who opted for the shame method.