Before I give specific book recommendations, I should comment a bit about periodization in Ethiopian history since it is relevant. In the post-Jesuit years (c. 1632), there are a couple general periods. The early eighteenth century to about the mid eighteenth century is, broadly, a period of decentralization and weakness. While the empire is still intact and a solid entity, it is definitely moving away from the "medieval" (a finnicky term in of itself but that's a separate discussion) period. C. 1750 to 1855 is the Zemene Mesafint, or the Era of Princes; this is a period where Ethiopia is split into several distinct regions with no central authority. While the imperial bloodlines still rule different regions, nobody has uniform power. This arguably changes in 1855, with Emperor Tewodros II ascended and declared himself Negus Negast, or King of Kings. Although central control takes several more emperors, modern Imperial Ethiopia is a distinct age that lasts until the Derg revolution in 1974. I mention this briefly because you will find scholars focus on different parts of the post 1600 era, with most focus on major moments like the Italo-Ethiopian Wars and, to a lesser extent, the British Expedition in 1868. You will not see as many books that cover both the late medieval period and the Modern Imperial period.

Now onto the actual recommendations! These are all books that still see active use among historians of Ethiopia.

Richard Pankhurst's The Ethiopians is a fantastic general text about Ethiopia, covering as far as antiquity (yes) but focuses mostly on the past few centuries. On the modern period, Bahru Zewde's A History of Modern Ethiopia, 1855 - 1991 and Paul Henze's Layers of Time are both excellent. Sheed A. Adejumobi's The History of Ethiopia also covers the more modern period, but has a greater emphasis on Ethiopianism as an identity among both national Ethiopians and the diaspora. There are always the more specialized works, like Gebru Tareke's The Ethiopian Revolution: War in the Horn of Africa or James McCann's People of the Plow: An Agricultural History of Ethiopia, 1800 - 1980.

There are a number of topics that have not had much recent English-language work. The Era of Princes, for example, has not had much systematic attention since the 1968 work by Mordechai Abir entitled The Era of the Princes: the Challenge of Islam and the Re-unification of the Christian Empire, 1769-1855. While a bit dated, it's still a fine book.

Hopefully this is a decent starting point. Please let me know if you have any further questions or if you are curious about any specific books.