ISE Principles of Corporate Finance from Richard Brealey, Stewart Myers and Franklin Allen is probably one of the best books you should read to start with Corporate Finance.
Principles of Corporate Finance is the worldwide leading text that describes the theory and practice of corporate finance. Throughout the book, the authors show how managers use financial theory to solve practical problems and as a way to respond to change by showing not just how, but why companies and management act as they do. This text is a valued reference for thousands of practicing financial managers.
Get it here: