This book provides an introduction to communication technology, covering modern methods of data transmission and data security based on the information theory established by Claude Shannon. Shannon's information theory departs from the meaning of data and, simply put, relies solely on their statistical properties. This enables a mathematical definition of information for the first time. Against this backdrop, the author introduces the fields of source and channel coding, transmission channels, decision theory, modulation techniques, as well as basic protocols and data security. He exemplarily presents selected models of communication technology, practical methods, techniques, and algorithms. A comprehensive appendix provides the fundamentals of probability theory, Fourier analysis, and signal and system theory.