So, I think you may have to be more specific - I'm going to assume you mean one book or source which covers the entire Israel-Palestine/Arab conflict which is entirely impartial (does not overtly favor one narrative), presents only facts that 100% undisputed (by all sides of the conflict), and without the author making some kind of argument about how this history affects current events and narratives.
Unfortunately, that book does not exist - though I would argue that no history book on any topic would fit that criteria. Imagine a book on the American Civil War, or on WWII, which was entirely impartial and written without opinion. Additionally, 'facts' will change as new findings, and new historical research, reveals new pieces of information which will challenge previously understood and accepted narratives.
What I would recommend instead is perhaps taking first a very generalist, accepted history - but then bolstering that history with a set of sources which examines the Israel-Palestine/Arab conflict through lenses that are not commonly covered in a simple chronology. To start, the sections on Israel/Palestine in "A History of the Modern Middle East" by William L. Cleveland, and "A History of the Arab Peoples" by Albert Hourani would give a good understanding of the outlines of the origins of the conflict, its causes, and its trajectory to at least the end of the 20th century.
I would then suggest works that challenge the dominant narratives of the conflict. "The Gun and the Olive Branch" by David Hirst is an excellent place to start, which presents an (in my opinion) even handed narrative of the Israel-Palestine conflict, but which also notes how the dominant narratives of both sides of the conflict, Israeli and Arab, have been distorted by political developments and do not hold up to factual scrutiny. I would also recommend the work done by several Israeli historians (often referred to as the 'New Historians'), which are works of revisionist history. Avi Shlaim and Ilan Pappe have both written excellent books and articles challenging Israeli narratives on the foundation of Israel and the early Arab Israeli wars; Shlaim's recent "Israel and Palestine: Reappraisals, Revisions, Refutations" is a good starting point, and Pappe's "The Ethnic Cleansing of Palestine" and "A History of Modern Palestine: One Land, Two Peoples" are both good starting points. While I do not agree with Benny Morris or his conclusions, several of his books such as "1948 and After: Israel and the Palestinians" are also fine pieces of work which are grounded in good research.
I would also read "Palestine And The Palestinians" by Samih K. Farsoun and Christina E. Zacharia for the specific perspectives of the Palestinian people in the modern era, both before and after the creation of Israel. For a look at what the region looked like on the eve of mass Jewish immigration to Palestine, "Jerusalem 1913: The Origins of the Arab-Israeli Conflict" by Amy Dockser Marcus examines the interactions between the pre-WW1 Palestinian community, the local Jewish community, and recently arriving Zionist immigrants. Finally, James Barr's "A Line in the Sand: Britain, France, and the Struggle for the Mastery of the Middle East" is an excellent piece of work using French and British diplomatic archives which details how the initial conflict was a part of a much wider contest in the region between Britain and France both during and after WW1 and WW2.
I hope you find this useful, and indeed, I hope you read some or all of these. Unfortunately the history of the Israel-Palestine conflict is one of competing narratives: some true, some patently false, and most with elements of both.
Hi there! Have you checked the booklist? It has a large number of suggestions. Unfortunately you're never going to find unopinionated histories, especially not on an inherently political issue like the Israel-Palestine conflict. How one evaluates the evidence and especially, how one forms a conclusion, relies to a certain extent on value judgments concerning rights, duties, international law and relations, right to self-determination, the nature of antisemitic currents in the Arab world, etc.
The best you can do is to read several perspectives and in the end, form a judgment of your own.
Good luck!