I am quite interested in understanding smooth 4-manifolds. What are the necessary prerequisites in order to start my study? Also can you please suggest me some good books from where I can start? Thanks in advance.
Edit : I have studied Hatcher upto Cohomology, first 3 chapters of Milnor's Morse Theory, Riemannian Geometry by Petersen (expecting to finish within one month), Complex Geometry from Griffiths and Harris (chapter 0 and have started chapter 1), basic knowledge of connection and curvature on fibre bundles.