<p>The lattice of varieties of distributive pseudo-complemented lattices is completely described, viz. a chain of type W + 1. Moreover, each variety is determined by a single equation in addition to those equations which define distributive pseudo-complemented lattices. Characterizations of distributive pseudo-complemented lattices satisfying a certain equation are given which turn out to be generalizations of L. Nachbin's result for Boolean algebras and the results for Stone algebras obtained by G. Gratzer-E. '11. Schmidt and J. C. Varlet. </p> / Thesis / Doctor of Philosophy (PhD)