Understanding fields using strings: A review

In addition to being a prime candidate for a fundamental unified theory of all interactions in nature, string theory provides a natural setting to und erstand gauge field theories. This is linked to the concept of 'D-branes': extended, solitonic excitations of string theory which can be studied using techniques of string theory and which support gauge fields localized along their world-volumes. It follows that the techniques of string theory can b e very useful even for those particle physicists who are not specifically i nterested in unification and/or quantum gravity. In this talk I attempt to review how strings help us to understand fields. The discussion is restrict ed to 3+1 spacetime dimensions.