The available microwave and millimeter-wave spectra of methanol, CH3OH, and its most abundant isotopomer,13CH3OH, are critically reviewed and supplemented with spectral frequency calculations derived from rotation-internal rotation analyses. For both species, global analyses of the torsional ground state,&ngr;t=0, and the first excited torsional state,&ngr;t=1, have been carried out in which all observed spectral lines are reproduced to within their measurement uncertainties. References are given for all data included. The primary objective of this review is to provide radio astronomers with complete spectral coverage of rotational transitions from 500 MHz to 1 THz, including the lower state energy and line strength for each transition, over the range in rotational quantum numberJfrom 0 to 26. ©1997 American Institute of Physics and American Chemical Society.Key words:Internal rotation (or torsion); interstellar molecule; isotopomer; line strength; methanol; microwave and millimeter-wave spectra; radio astronomy; rotational transitions.