Alan Lester is an English historian, historical geographer and author who has worked for Sussex University since 2000. He was appointed Professor of Historical Geography in 2006. He is known for his research on imperial networks, colonial humanitarianism and imperial governance. In Colonisation and the Origins of Humanitarian Governance he and co-author Fae Dussart analysed the ways in which men considering themselves humane oversaw the destruction of Indigenous societies. His book Ruling the World: Freedom, Civilisation and Liberalism in the Nineteenth-Century British Empire, he examined how imperial governance worked 'everywhere and all at once' across the British Empire at key moments during the nineteenth century. Lester gave the Distinguished Historical Geographer Lecture at the 2022 Association of American Geographers annual conference. He is co-editor of the Manchester University Press' Studies in Imperialism research monograph series. Lester has been described as “the pioneer of the idea” of “a key concept much used in recent ‘new imperial history’ writing … that of the imperial network”. Lester has written of his concern at the recent politicisation of imperial history, and critiqued British academic Nigel Biggar's representation of colonialism.