Single mode ruby laser radiation (694 nm) and an atomic beam apparatus have been used in the study of the three photon ionization of Na, K, Rb, and Cs atoms. The process in all cases is nonresonant, the observations being consistent with a rate given by W3F3 where F is the photon flux. The values obtained for W3l (linear polarization) and W3C (circular polarization) and the ratio W3c/W3l are discussed in relation to recently calculated results and the few other experimental results available. Discrepancies well beyond the assigned errors exist between experimental and calculated results.