Since their introduction in 1994, the Seiberg-Witten invariants have becomeone of the main tools used in 4-manifold theory. In this thesis, we will use these invariantsto identify sufficient conditions for a 3-manifold to fibre over a circle. Additionally, wewill construct several examples of genus 1 and 2 surface bundles and prove their totalspaces are spin 4-manifolds.Â