Covering: 1998–2000. Previous review: Nat. Prod. Rep., 1999, 16, 97

This review covers recently-published experimental information on the biosynthesis of terpenoids in the range C₅–C₂₅. In addition to sections on the mevalonate and mevalonate-independent (deoxyxylulose phosphate) pathways, the review considers in turn hemiterpenoids, polyprenyl diphosphate synthases, monoterpenoids, sesquiterpenoids, diterpenoids, and sesterterpenoids. The literature from January 1998 to December 2000 is reviewed, with 248 references cited.