A compilation of the volatile and semi-volatile constituents of agarwood, the infected fragrant heartwood of some Aquilaria species, mainly A. malaccensis, A. sinensis and A. crassna, is presented. This high-priced wood has a long tradition in religious ceremonies as incense and its essential oil is well appreciated in fine perfumery. More than 150 compounds have been identified so far, mostly sesquiterpenoids, chromones and volatile aromatic compounds. The scarce knowledge of their organoleptic properties is summarized. Studies on the chemistry of agarwood smoke are discussed. Emphasis is given to structural and analytical aspects. Copyright © 2011 John Wiley & Sons, Ltd.