The article "Doxographi Graeci" by Herman Alexander Diels introduced a new way of studying ancient philosophers by analyzing references in existing texts. Diels examined writings by various authors to uncover information about Presocratic philosophers whose original works are lost. By tracing the sources and evaluating their reliability, Diels made significant advancements in understanding these early thinkers. His work laid the foundation for the critical discipline of doxography, which involves editing and analyzing extracts from classical texts to learn about ancient philosophical ideas.