I'm going to break my self-imposed rule against posting a book that I know has been posted before . . . .
The Philosophy Book (Big Ideas Simply Explained). Only 99 cents right now (I paid $1.99 a while back

).
I have trouble understanding philosophy. I need all the help that I can get (I think that I halfway have figured out Plato's imagery of the Cave and the shadows thingie, though). I think that the 352 pages of this tome will help a lot, but I haven't had a chance to open my copy--it's a GBTI. This book seems to be a good one--Some ratings: 4.5 (200) at Amazon; 4.16 (1,737).
https://www.amazon.com/dp/B00TK7U4A0.