This casebook argues that standardized psychological testing is superior to traditional assessment methods, presenting a multitrait, multimethod approach that leads to more convincing case resolutions and effective treatment planning. Rather than using a typical case study approach, this casebook analyzes clusters of similar cases, including 65 that represent common diagnostic issues, questions, and examinations in mental health practice. Covering ten major types of cases, from suspected learning disorders to forensic evaluations and child custody examinations, the book identifies unifying themes and provides a comprehensive content base for each issue, question, or examination type. Each chapter begins with detailed background information to explain the case type, helping readers understand what to look for before presenting one or more illustrative examples. These examples show how to classify referrals by examination type, presenting issues, or key questions, and how to resolve them using a data-driven test battery. Spores helps the reader understand what they are looking for and demonstrates how identifying the commonalities among various cases can lead to effective test-based strategies for their efficient resolution. The casebook is written as a primary text in both advanced undergraduate- and graduate-level courses covering psychological testing, along with being on the shelves of many mental health clinicians as a reference text to help them work through difficult patients on their caseloads.