This review is devoted to strings and branes. Firstly, perturbative string theory is
introduced. The appearance of various types of branes is discussed. These include
orbifold xed planes, D-branes and orientifold planes. The connection to BPS vacua
of supergravity is presented afterwards. As applications, we outline the role of branes
in string dualities, eld theory dualities, the AdS/CFT correspondence and scenarios
where the string scale is at a TeV. Some issues of warped compactications are also
addressed. These comprise corrections to gravitational interactions as well as the
cosmological constant problem.