The intended reader of this text is typically a last-year undergraduate, a graduate student in economics, or a researcher. People in connected fields (sociology, geography, urban planning, regional science, transportation, etc.) as well as policy makers with some background in economics should also be interested, especially in the last part of the book. Indeed, the techniques used in this book are not complicated and are now quite standard, and the main requirement is to be interested in the issues and have a good ability to use simple models and algebraic manipulations. I have homogenized the different models and the different chapters of this book by using the same notations and the same type of approach throughout. So the reading should be quite smooth. I have also included various appendices, which should help the reader understand the different chapters.

This book is the outcome of my research, which started twenty years ago. It has thus been a long time in the making. In August 1987, when I finished my master's degree in economics and econometrics at Université de Paris 10 (Nanterre), I was looking for a possible dissertation topic for a PhD. I had the chance to meet Gerard Ballot, professor at Université Pantheon-Assas (Paris 2), who suggested that the analysis of spatial labor markets could be an interesting and challenging topic. I decided to embark on this journey, having for sole reference the seminal paper of Harris and Todaro published in American Economic Review in 1970. In my dissertation, I studied the spatial aspects of labor markets, from both a theoretical and empirical perspective.