This introductory textbook covers all the knowledge of financial mathematics that the author would have liked to have had when starting his career in the insurance industry. The reader receives an intuitive introduction to the financial mathematical analysis of deterministic cash flows and fixed-income securities, as well as to the stochastic modeling of interest rates. This enables the reader to learn the essential foundations for further analysis of complex financial instruments. The book is mathematically rigorous and practically illustrative. The practical application is demonstrated through numerous examples and illustrations, as well as 100 exercises with solutions.