Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is one of the most common bioanalytical methods used today, offering ultrasensitive detection in the several-partsper- million (or even parts-per-billion) range. The unique specificity of tandem mass spectrometry provides greater flexibility for LC separations, expanding the applications that can utilize LC/MS/MS. In this article, we take a closer look at LC/MS/MS to see how this innovative method works and how key innovations in its design are set to change the life science landscape.