Methanol has a rich torsion-vibration-rotation spectrum extending from the millimeter and submillimeter regions all the way through the far-infrared (FIR) and up to the near IR. High- resolution studies of the lower vibrational modes have revealed numerous perturbations arising from Fermi, Coriolis, and asymmetry resonances. A remarkable number of the perturbed energy level systems contribute to the extensive FIR laser emission observed from methanol isotopomers optically pumped by CO2 lasers. FIR laser lines involving perturbed IR levels have been invaluable aids in assigning the FIR and IR spectra and thereby locating the specific energy channels through which the CO-stretching, CH3-rocking and OH-bending vibrational modes interact with eachother, frequently via torsion-mediated coupling.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.