Ontology without Axioms --; Le?niewski's Analysis of Russell's Paradox --; Logic and Existence --; Le?niewski's Calculus of Names --; On Le?niewski's Ontology --; Ontology: Lesniewski's Logical Language --; On Le?niewski's Elementary Ontology --; Studies in Le?niewski's Mereology --; On the Definition of Mereological Class --; Consistency of Le?niewski's Mereology --; The Dependence of a Mereological Axiom --; Relation of Le?niewski's Mereology to Boolean Algebra --; Index of Names.