Measuring and Testing - the emphasis is on the "and." This textbook illustrates the connection between measuring and testing, measurement models, and testing theory. It enables students in both undergraduate and graduate studies to develop a profound understanding of these two typically separate areas. This is facilitated by a well-crafted didactic concept: the book is divided into introductory, application, and advanced chapters. Each chapter includes numerous examples, learning objective control questions (with answers), and exercises (with solutions). Key points are highlighted in the margins, summaries of the most important chapter statements are presented in boxes, and colored backgrounds and pictograms, along with chapter summaries and references to further literature, aid in quick orientation.