The textbook describes the evaluation of secure and insecure real and financial investments under the assumption of arbitrage-free and frictionless financial markets. The focus is on investment valuation according to the duplication principle. This valuation principle underlies both the classic net present value formula for real investments and the now-classic valuation formula by Black, Scholes, and Merton for stock options, as well as newer variants for interest and credit derivatives. All essential results are clearly summarized in so-called properties and illustrated with many illustrations and examples. Exercises provide a solid foundation for courses in the finance major, for continuing education seminars, and for independent learning of the content.