Psychometrics: An Introduction by Richard Michael Furr
Focusing on the conceptual understanding of psychometric issues such as validity and reliability this textbook introduces psychometric principles at a level that goes into more detail than introductory undergraduate texts, yet also more intuitive than more technical publications intended for postgraduate level.
By emphasizing conceptual development and practical significance over mathematical proofs, this book assists students in appreciating how measurement problems can be addressed and why it is important to address them.