'Et mai ..... si j'avait su comment en revenir. One service mathematics has rendered the je n'y semis point aUe.' human race. It has put common sense back Jules Verne where it belongs, on the topmost sheJf next to the dusty canister Iabclled 'discarded non· The series is divergent; therefore we may be sense'. Eric T. Bell able to do something with it. O. Heaviside Mathematics is a tool for thought. A highly necessary tool in a world where both feedback and non­ linearities abound. Similarly, all kinds of parts of mathematics serve as tools for other parts and for other sciences. Applying a simple rewriting rule to the quote on the right above one finds such statements as: 'One service topology has rendered mathematical physics .. .'; 'One service logic has rendered com­ puter science .. .'; 'One service category theory has rendered mathematics .. .'. All arguably true. And all statements obtainable this way form part of the raison d'etre of this series.

One. Oscillations and Waves in Linear Systems.- 1. Linear Oscillators.- 2. Oscillations in a System with Two Linked Oscillators.- 3. Oscillations in an Ensemble of Non-Interacting Oscillators.- 4. Oscillations in Ordered Structures. Limit for a Continuous medium. Waves. Dispersion.- 5. Properties of Waves with Small Amplitudes in Continuous media.- 6. Stability and Instability of Linear Systems with Discrete Spectra.- 7. Stability of Distributed Systems with Continuous Spectra.- 8. Propagation Velocity of Waves.- 9. Energy and Momentum of Waves.- 10. Waves with Negative Energy. Linked Waves.- 11. Parametric Systems and Parametric Instability.- 12. Adiabatic Invariants. Propagation of Waves in Inhomogeneous Media.- Two. Oscillations and Waves in Nonlinear Systems.- 13. The Nonlinear Oscillator.- 14. Periodic Self-Excited Oscillations.- 15. General Properties of Nonlinear Dynamic Systems in Phase Space.- 16. Self-Excited Oscillations in Multifrequency Systems.- 17. Resonance Interactions between Oscillators.- 18. Simple Waves and the Formation of Discontinuities.- 19. Stationary Shock Waves and Solitons.- 20. Modulated Waves in Nonlinear Media.- 21. Self-Excited Oscillations in Distributed Systems.- 22. Stochastic Dynamics in Simple Systems.- 23. The Onset of Turbulence.- 24. Self-Organization.- References.