In this completely updated and expanded edition of a classic bench manual, hands-on experts take advantage of the latest advances in ribozyme, DNAzyme, and RNA interference technologies to describe in detail the exciting and successful methods now available for gene inactivation in vitro and in vivo. Their optimized techniques employ hairpain ribozymes, DNAzymes, hammerhead ribozymes and derivatives, group I intron ribozymes, Rnase P ribozymes, and siRNAs, as well as general methods for RNA structure analysis, delivery of oligonucleotides, and gene therapy. Also provided are novel methods for identifying accessible cellular mRNA sites; group I intron and RNAse P ribozymes protocols for effective design, selection, and therapeutic applications; and the latest RNAi methods for sequencing-specific gene silencing in a wide variety of organisms. Comprehensive and up-to-date, Ribozymes and siRNA Protocols synthesizes for experienced and novice investigators alike the exciting advances in understanding nucleic acid enzymes and demonstrates how they may be used to analyze gene function and target validation, and to productively develop new therapeutics for human diseases.