I think the classic /r/askhistorians answer would be that there may well not be any "best" book on any particular historical event or issue, particularly for one so complicated as the Israeli-Palestinian conflict. Quoting from a recent post on historiography:

There is extremely rarely a single "definitive" work in the field of history. There are famous works, there are important works, there are even widely accepted "best" works on a topic. We rarely, however, find "the" work on a topic. Historical knowledge and understanding is built up through the aggregate work of many historians working on a topic. Maybe they approach similar questions from different angles, maybe they ask different questions about the same topic, maybe they use different methodological or theoretical approaches and so forth. The most complete picture you really can get, to the extent you can at all, comes from familiarizing yourself with the literature in that field. That doesn't mean everything is equally "right" or equally valuable. But it does mean that history is a kind of collective project. This is also why citations are so important. It's not just that you are saying where you got an idea, but you are placing your own work within that larger discussion on the topic. So when you are writing history you aren't just having a conversation with the past, you are also having a conversation with other historians.

That said, since you're probably not looking to do an in-depth study of the field (at least, I probably wouldn't in your situation), I'll recommend that you take a look at the excellent list of books and resources that /r/askhistorians has developed. You can find that here and the list you're looking for here - although the section is labeled "Israeli history," there are several books on there about the Israel-Palestine conflict since, of course, there can be no history of modern Israel without discussing the Palestinians to a great extent.

I think your hope for an unbiased book about the conflict might be wishful thinking. Don't knock the pro-Israel books as you will learn a lot, and the most important part of the conflict is understanding the perspective of each side. That being said, I think taking a look at the different maps of Palestine and Israel is a good place to start

Israel/Palestine by Alan Dowty, This is a great resource for information from both sides. I used this book as a reference in several papers in undergrad.

The Routledge Atlas of the Arab-Israeli Conflict by Martin Gilbert. This is to make sense of it all. This book rocks! Again I utilized this book throughout all of my studies surrounding the conflict. Understand the geography.

If you are looking for more Palestinian standpoint books I would lead you to looking into memoirs. I can get you some more names if you want but I would have to look through some stuff. Hopes this helps ya!