Contents: Preliminaries. - Elements of the theory of topolo- gical groups. -Integration on locally compact spaces. - In- variant functionals. - Convolutions and group representa- tions. Characters and duality of locally compact Abelian groups. - Appendix: Abelian groups. Topological linear spa- ces. Introduction to normed algebras. - Bibliography. - In- dex of symbols. - Index of authors and terms.