Strings and linear topologies.- Metrizable topological vector spaces.- Projective limits of topological vector spaces.- Inductive limits of topological vector spaces.- Topological direct sums, strict inductive limits.- Barrelled topological vector spaces.- The Banach-steinhaus theorem.- Barrelled spaces and the closed graph theorem.- Barrelled spaces and the open mapping theorem.- Completeness and the closed graph theorem.- Bornological spaces.- Spaces of continuous linear mappings and their completion.- Quasibarrelled spaces.- Boundedly summing spaces.- Locally topological spaces.- Spaces with an absorbing sequence.- ?-locally topological spaces.- (DF)-spaces and spaces with a fundamental sequence of compact sets.- Some examples and counter examples.