The document discusses preparative high performance liquid chromatography (prep HPLC). It begins with an introduction to prep HPLC, noting it was developed in the 1970s to increase throughput and separation power compared to analytical HPLC. The principles, instrumentation, and differences between analytical and prep HPLC are then described. Various hyphenation techniques for prep HPLC including with mass spectrometry and flash chromatography are also covered. Finally, applications of prep HPLC like purification and an example study using it to purify saffron metabolites are summarized.