Johann Gustav Droysen’s Geschichte Alexanders des Grossen, first published in 1833, essentially founded the modern academic study of Alexander the Great and the Hellenistic world. Writing in German, Droysen drew on classical sources to reconstruct Alexander’s campaigns from Macedonia through Persia and into India, coining the term "Hellenismus" to describe the cultural fusion that followed the conquests.
This is a work of major historiographical significance: rigorous, ambitious, and deeply influential on all subsequent scholarship about ancient Greek civilisation. Note: this text is in German.