This is the sixth in a series of volumes investigating, discussing and explaining the application of instrumental spectrometric and spectroscopic techniques to the determination of molecular structures. This volume concentrates on the analysis of twenty common medicines. The series is intended to bridge A-level (UK) and K12 (USA) courses and the first two years of university chemistry studies. Each chapter follows the same style with an introductory page discussing the application and history of the development of the medicine with a summary of the elemental data and the formula mass, leading to the determination of the empirical and molecular formulas of the compound. We then continue with the analysis of the infrared, mass and proton & carbon-13 NMR spectra.