In recent times, the concept of intelligence has undergone drastic changes and, in some cases, the term “intelligence” has been avoided. This book is an attempt to clarify the concept of intelligence. The theory that forms the basis for this book is referred to as PASS. It stands for Planning, Attention, Simultaneous, and Successive processes. These processes form a complex and interdependent system which 1) helps us understand the nature of individual differences, 2) provides a framework within which to conceptualize assessment, and 3) leads directly to theory-based mediation. After presenting the PASS theory and the body of literature that supports it, the authors describe measures employed in assessment and remediation.