Table of Contents:RNA interference in mammalian cell systems.-RNAi pathway in C. elegans: The Argonautes and collaborators.- Genetics and biochemistry of RNAi in Drosophila.- Role of Dicer in post-tran- scriptional RNA silencing.- The mechanism of RNase III action: How Dicer Dices.- micro RNA metabolism in plants.- Structure-function relationships among RNA- dependent RNA polymerases.- RNAi-mediated chromatin silencing in fission yeast.- A role for RNAi in heterochromatin formation in Drosophila.- RNA mediated transcriptional gene silencing in human cells.- RNA silencing in mammalian oocytes and early embryos.- Identifying human MicroRNAs.- Subject index.