The lipids in biological systems used to be seen as little more than energy reservoirs and insulating materials. Then they were found to serve additional functions. Lipids were identified as chemical messengers and as the main structural components of organelle and cell membranes.1 To perform all these functions, lipids occur in myriad forms. Indeed, lipids are so diverse that they defy comprehensive study—or they did, until the advent of lipidomics technologies such as liquid chromatography–mass spectrometry.
