1. 1. This is a revised and updated version of the chapter published in the rst edition: Itokawa, H., Wang, X. and Lee, K.H., Homoharringtonine and related compounds, chap. 4, in Anticancer Agents from Natural Products, Cragg, G.H., Kingston, D.G.I. and Newman, D.J., Eds., CRC Press, Boca Raton, FL, 2005, 47–70.