Twisted Alexander polynomials and fibered 3-manifolds

In a series of papers the authors proved that twisted Alexander polynomials detect fibered 3-manifolds, and they showed that this implies that a closed 3-manifold N is fibered if and only if S^1 x N is symplectic. In this note we summarize some of the key ideas of the proofs. We also give new evidence to the conjecture that if $ is a symplectic 4-manifold with a free S^1-action, then the orbit space is fibered.