Foreword xi Preface to the Second Edition xv Preface to the First Edition xvii Acknowledgments xxi 1 Building Abstractions with Procedures 1 1.1 The Elements of Programming 4 1.2 Procedures and the Processes They Generate 31 1.3 Formulating Abstractions with Higher-Order Procedures 56 2 Building Abstractions with Data 79 2.1 Introduction to Data Abstraction 83 2.2 Hierarchical Data and the Closure Property 97 2.3 Symbolic Data 142 2.4 Multiple Representations for Abstract Data 169 2.5 Systems with Generic Operations 187 3 Modularity, Objects and State 217 3.1 Assignment and Local State 218 3.2 The Environmental Model of Evaluation 236 3.3 Modeling with Mutable Data 251 3.4 Concurrency: Time Is of the Essence 297 3.5 Streams 316 4 Metalinguistic Abstraction 359 4.1 The Metaciricular Evaluator 362 4.2 Variations on a Scheme--Lazy Evaluation 398 4.3 Variations on a Scheme--Nondeterministic Computing 412 4.4 Logic Programming 438 5 Computing with Register Machines 491 5.1 Designing Register Machines 492 5.2 A Register-Machine Simulator 513 5.3 Storage Allocation and Garbage Collection 533 5.4 The Explicit Control Evaluator 547 5.5 Compilation 566 References 611 List of Exercises 619 Index 621