I read your post and could definitely sympathize. I have been in a similar situation, where at age 41, I'm realizing that lack of confidence has hobbled me more than ability. I'm doing self study in subjects that are of interest, such as math and electronics, psychology, and even physics. As for what math book...perhaps a bit tongue in cheek, but I can seriously recommend looking at the 'For Dummies' series of books. I've read about 3 of these on various topics, and will be getting Latin for Dummies and Calculus for Dummies soon. I strongly recommend taking a look at this series...only the title is unfortunate, these books are excellent introductions and should not be ignored because they are titled 'for dummies'. Also, I applaud your efforts to improve yourself and strongly encourage you to reach for your potential.