A survey of K-theory.- Characterizing Ext(X).- Almost commuting algebras.- Extensions of C*-algebras and K-homology.- Bundles and sheaves are equivalent in the category of banach spaces.- Topological obstructions to perturbations of pairs of operators.- On algebraic K-theory and the homology of congruence subgroups.- Configuration spaces.- Extensions of C*-algebras and the reducing essential matricial spectra of an operator.- K-homology theory and algebraic K-theory.- Some remarks on operator theory and index theory.- Factors of type III.- Twisted products of Banach algebras and third ?ech cohomology.- H-cobordisms, pseudo-isotopies, and analytic torsion.
