Israeli Apartheid: A Beginner's Guide
By Ben White
A great place to start. A short book of about 100 pages, it includes a glossary of important terms, a list of resources for more info, and an FAQ section that responds to points that people frequently make in debates.
One fact I learned from this book: During the second intifada in 2000, the IDF fired 1.3 bullets before there was any violence from Palestinians. According to scholar Derek Gregory: "The IDF responded with astonishing violence; no Israeli civilians were killed by Palestinians until November, but by October Israel had already deployed high-velocity bullets, helicopter gunships, tanks, and missiles against the Palestinian population."