The study of ancient science and its relations with Greek philosophy has made a significant and growing contribution to our understanding of ancient thought and civilisation. This collection of articles on Greek science contains fifteen of the most important papers published by G. E. R. Lloyd in this area since 1961, together with three unpublished articles. The topics range over all areas and periods of Greek science, including astronomy, cosmology, biology and medicine from the earliest Presocratic philosophers to Ptolemy and Galen. Several focus on important methodological problems: others on the social background to Greek science, on the motivations of ancient Greek scientists, their aims and the implicit assumptions that influenced their work. In each case the article is preceded by an introduction that assesses scholarly debate on the topic since the original publication. Professor Lloyd also suggests modifications and developments to his own position in the light of those debates and his own further research.