Nonlinear studies, by and large, have emerged in a variety of disciplines such as physical, chemical, biological, social and technological sciences, and in particular, differential equations. As trends go, there is every likelihood that an undergraduate curriculum in areas of mathematics, science, technology and even social sciences should start reflecting a qualitative approach, mainly through differential equations. Hence, this book is intended not only for students of mathematics, but also for a wider readership.

The genesis of this book can be described essentially as an outgrowth of my postgraduate teaching. I am especially confident of the content, thanks to the classroom notes my students assiduously took down over the years and later passed on to me to structure this volume.

I must confess, I have had the privilege of sitting through the valuable lectures of leading personalities, such as Prof Rene Thom, Delegue de l'Academie des Sciences, France, Prof E C Zeeman, Warwick University, UK, Prof D J Chillingworth, University of Southampton, UK and Prof Michael A B Deakin, University of Monash, Australia, on catastrophes and bifurcations, at the Jadavpur University, Kolkata. I must also mention about my own exposure and interactions with the faculty at ICTP, Trieste, Italy, under the leadership Prof E C Zeeman, on a course on ‘dynamical system’.

Problems have been set in the book with a view to engage students' creativity as well as exercise their mental prowess.