I would say it really depends on the field; the book list on this reddit has quite a few of the highlights. Here are some of what I believe to be key authors from my fields.
Pacific History; only putting a few, cutting myself off before I make this super long.
- Greg Denning [also key figure for the writing of ethnographic history and all around an awesome author/historian].
- Matt Matsuda; his recent work has been pretty hot, especially with Americanists looking out into the Pacific.
- Epeli Hau'ofa; especially his essay "Our Sea of Islands" any book discussing the ocean or indigenous peoples has an obligatory reference to it.
- J.W. Davidson; his essay "Problems of Pacific History" is usually pinpointed as the kickoff to modern Pacific History and the foundation of Pacific Island Studies as a field.
- Marshall Sahlins; his anthropology work is referenced often, especially his vitriolic debate with Obeyesekere.
- Nicholas Thomas; extremely prolific historian, "Entangled Objects" is I believe his most cited work and deals with how the meaning of objects changes when they are exchanged.
- Alan Moorehead; his popular history book "The Fatal Impact" is probably one of the most cited but never read books on the Pacific. Strangely, this popular writer's overview of Captain Cook's voyages, has became code for a certain approach to Pacific history, which is rather at odds with the actual text of the book (which is why I say I usually get the feeling most authors have no actually read it).
Environmental History
- William Cronon; especially "Changes in the Land" and his essay "The Trouble with Wilderness"
- J.R. McNeill; "Something New under the Sun" is well regarded, but I like "Mosquito Empires" more.
- Alfred Crosby; can't avoid "The Columbian Exchange" or "Ecological Imperialism"
- David Blackbourn, Richard Grove, and James McCann are all popular
- Jared Diamond; and "Guns Germs and Steel" though a popular-history work, is still often cited- especially in regards to the opennness of the reading public to environmentally aware/ driven history books.
In World History, it's great if you know the following with a few brief (perhaps too brief) notes about why they are good to know
- Leopold von Ranke- focus on history as science, universal histories
- Arnold Toynbee- first modern attempt at a 'civilizational' approach to world history
- William McNeill- gradual breaking with civilization approach, focus on connections
- Stavrianos- another early attempt at writing a world encompassing history
- Jerry Bentely- helped found World History Association & its journal; focus on exchanges/contacts as a way to study world history
- Immanuel Wallerstein; marxist inspired world systems theory
- Janet Abu-Lughod; argued world systems predate rise of Europe by some time
- Patrick Manning; maritime narratives
- David Christian; big history
- Andre Gunder Frank; decentering europe vis a vis china
- Kenneth Pomeranz; similar to Gunder Frank
- Fernand Braudel; Mediterranean- long duree- annales school history
- Bruce Mazlish; global history is better than world history
- Benedict Anderson; imagined communities, birth of nation states/community
- Eric Hobsbawm; Invented Traditions- how nation/states make themselves appear timeless