The Book of Abraham is so many things in one book that I struggled to gather my thoughts in a coherent review. Plot-wise it's the story of Halter's family, starting in 70AD with the destruction of Jerusalem, and ending in 1943 with Halter's grandfather Abraham in the Warsaw Ghetto. As Halter follows his ancestors, the story moves through Jewish settlements in North Africa, Arab-ruled Spain, France, Italy, the Ottoman Empire and eventually Poland. Halter's family is presented as generations of scribes then printers, which means the characters often interact with historical figures like Gutenberg, Rembrandt and Gracia Mendes Nasi (side note: I had never heard of her and spent a whole afternoon looking up her story).
Since there are so many centuries crammed into 700 pages, the characters aren't always hugely developed, and some of the stories remain more anecdotal. For that reason I found the first 100p or so not hugely gripping, but that changed later in the book once the characters get more fleshed out and the historical/geographical setting becomes more developed. It's also a hard read at times (reading about centuries of pogroms is tough and required a breather every now and then, even if Halter never lingers on details) but a necessary one.
But beyond the main 'Halter family' plot, The Book of Abraham is about Jewish memory and history. As the family moves from one country to the next, most of the time to flee persecutions, it shows a vision of history that is fluid and ever moving, and very different from the rigid, limited-to-one-country version I was taught at school. If you grew up in a Christian society, this book makes you realise just how much this influences our current version of history. Here various religious groups coexist, influence events and governments. Thanks to the generations of scribes and printers, The Book of Abraham also gives a glimpse at Judaic literature and its body of sacred texts -- basically a whole society that existed parallel to anything that makes the school curriculum (I certainly had never heard of the Jewish Enlightenment!).
The book has had its controversies in recent years -- whether Halter used a ghostwriter, and whether some parts of his family's history was made up. To be entirely honest I don't find this relevant; it's obvious that the book combines a huge amount of historical research with a fictionalised narration of many characters, and Halter himself explains that in a few chapters. Ultimately the aim of the book isn't to present a "true" history of a family, but an epic work on Jewish history and memory -- and it does that perfectly.
PS: there's a sequel to this book called The Sons of Abraham, which picks up in the 50s and follows Halter's cousins in Argentina, France, Israel and Russia. Since it's focused on a few decades and only a handful of characters, it's faster-paced and even reads like a spy novel at times. Highly recommend it.