This wide-ranging collection of state-of-the-art techniques for the assay of phospholipid and phospholipid-derived second messengers allows the identification and quantification of signal pathway activation. The assays described cover all the major phospholipases (C, D, A2), as well as sphingomyelinase and associated metabolites. Additional protocols are provided for the assay of phosphoinositide 3-, 4-, and 5-kinase activity and for the separation and identification of phospholipids, diacylglycerol and sphingolipids, as well as their phosphoinositol, choline, and fatty acid metabolites. Detailed, step-by-step instructions make this book suitable for both the newcomer and the experienced investigator.