This fully updated volume describes methods and protocols for a number of drugs and toxins in a stepwise manner. Exploring the versatility and flexibility of mass spectrometry, the book covers the advantages of this technology, which typically include elimination of the need for special reagents such as antibodies, increased sensitivity and specificity, and multi-component analysis enabling the screening of tens to hundreds of compounds in a single assay run. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step and readily reproducible laboratory protocols, as well as tips on troubleshooting and avoiding known pitfalls.