Among contemporary historians, I rate the American historian Stephen Kotkin (Ph.D, UC Berkeley) at the top of a very short list. He focuses on Russian and Soviet politics and history, communism, global history, authoritarianism, and geopolitics. I learned a lot from him on the Stalinist era, and the life of Joseph Stalin. I couldn’t possibly read his biography of Stalin (three volumes, each 1000+ pages) but fortunately his talks and conversations provide what we non-specialists should know.
Another historian I like happens to be a farmer and a scholar: the classicist Victor Davis Hanson. He’s a conversative and comments on contemporary politics. VDH is an expert on military history, ancient warfare, ancient agrarianism, and the classics. VDH divides his time between Stanford University and Fresno, a small town in the Central Valley of California. He works on his family farm which has been with them for six generations.