I've read a ton of PF books and the two I'm going to recommend are old and will likely be scoffed at by others, but I understand your question and these two were instrumental in my quest for FIRE. (Reached in 2012, BTW.) They are both probably available used or better still, at your library. In no order of preference, "Ordinary People, Extraordinary Wealth" and "The Wealthy Barber". The former is worth its weight in gold for the first chapter alone, and the latter may have been updated since I first read it. It was out of date then, so look to see if there's an updated version. It's told in the form of a parable, so pretty easy to follow and understand.
Other than that, I found blogs such as MMM to be amazingly helpful, in part because the articles tend to be shorter and laser focused.