The book is divided into two parts. Although several major current SLA theories and models are described and discussed in Part One, “Following the Cognitive Tradition” the purpose of this part of the book is not to introduce the reader to the fundamental principles of existing theories and models. The main purpose of Part One is to illustrate the strong cognitive and experimental bias of current SLA models and theories and to advocate the application of a new framework that would remedy this bias. Part one consists of five chapters. Chapter 1 provides an overview of three major scientific research traditions: behaviorism, cognitive-computational, and dialogical. Chapter 2 provides a historical overview of SLA as a scientific field. The purpose of this overview is to explain the origin of this field and to illustrate the general trend of its adherence to the rules and norms established in other scientific fields. That is, after behaviorism, SLA turned to cognitive psychology for gui