Preface to the classics edition; Preface; Part I. Introduction to Perturbation Theory. 1. Root finding; 2. Regular perturbations; 3. Direct error estimation; Part II. Oscillatory Phenomena. 4. Periodic solutions and Lindstedt series; 5. Multiple Scales; 6. Averaging; Part III. Transition Layers. 7. Initial layers; 8. Boundary layers; 9. Methods of the WKB type; Appendix A. Taylor's theorem; Appendix B. The implicit function theorem; Appendix C. Second order differential equations; Appendix D. Systems of differential equations; Appendix E. Fourier series; Appendix F. Lipschitz constants and vector norms; Appendix G. Logical quantifiers and uniformity; Symbol index; Index.
