'Climate is a rather elusive entity,' wrote Helmut Landsberg in 1950 as he sorted through some twenty competing definitions. This volume of Osiris delves into that elusiveness, looking at the question of what 'climate' means from a historical perspective. In reaching back to the Greeks - who give the volume its title - it seeks to break the term free from its current exclusive association with atmospheric sciences in order to explore the term's long history of broader usage, in medical, geographical, agricultural, racial, and other contexts.