Corporate Finance, by Ross, Westerfield, and Jaffe is a popular textbook that emphasizes the modern fundamentals of the theory of finance, while providing contemporary examples to make the theory come to life. The authors aim to present corporate finance as the working of a small number of integrated and powerful intuitions, rather than a collection of unrelated topics. They develop the central concepts of modern finance: arbitrage, net present value, efficient markets, agency theory, options, and the trade-off between risk and return, and use them to explain corporate finance with a balance of theory and application. The well-respected author team is known for their clear, accessible presentation of material that makes this text an excellent teaching tool.

Marketing Management (12th Edition) (Marketing Management) by Kotler, Philip

A necessity
Sources of financing, cash flow analysis, net present value, discounting, etc, it's all here. Most of all - ratios. They will be back, so learn them the first time good.