If you take a college class on the subject, you'll undoubtedly be assigned two books: Mark Tessler's "A History of the Israeli-Palestinian Conflict" and Ruben & Lacquer's "The Arab Israeli Reader."

Tessler's book is a secondary source and it is literally the most thorough and even-handed history book in the history of the universe. It's about as thick as a phone book, and Tessler explores every nook and cranny of the conflict, trying to present the motives of both sides charitably while not hesitating to pinpoint areas of blame when he feels that either side was responsible for any sort of wrongdoing. In a sense, it's the perfect history book. But be forewarned: it's dense!

Ruben and Lacquer's book is a compendium of primary sources. It presents them in chronological order and features pretty much every document of note in the history of the conflict. It's a lot more accessible than Tessler's book since the documents tend to be fairly short.

There are many other great books, but those two are the gold standard.