Stoichiometric and nonstoichiometric hydroxyapatites are characterized by surface area, ICP, XPS and NMR MAS. The dehydration of methanol is shown to be unimolecular but poisoned by both alcohol and water, Rate constants and the ratio of the adsorption equilibrium constants of alcohol and water are obtained with the former appearing to be related to the surface Ca/P values. Infrared spectroscopy and temperature-programmed desorption and reaction show that hydroxyapatite, after exposure to methanol, contains surface methoxy groups and related experiments with deuterated methanol show that the dehydration process involves the interaction of methanol with surface protium.