The common theme in the essays of this book is the emergence and sur-
vival of spatial structures. How are economic structures created in an
otherwise homogeneous environment? The answer must be sought through an
analysis of economic forces that operate in the two dimensional contin-
uum of space. Ultimately these forces emanate from the fundamental fact
that spatial concentration is needed to reap increasing returns to
scale. i. e. to gather the fruits of the division of labour. Adam
Smith's dictum: "The division of labour is limited by the size of the
market" poses a fundamental question to spatial economic analysis: just
how do markets operate when extended over distances? Although these
essays were written at different times they all relate to the problem of
economic structures generated in spatial markets. They approach the
phenomena of spatial order from different angles, but it is hoped in a
connected and logically consistent way. We thank the editors and
publishers of the Annals of Regional Science for permission to reprint
parts of the articles "On the Shape and Size of Market Areas" and
"Population Growth and Dispersal" to be published this year. It is our
pleasure to thank Mrs. I. Strohlein for drawing several figures and Dr.
H. Mittermeier for compiling the index. Last not least we are grateful
to Mrs. B. Schwarzwalder for her patient job of typing and retyping this
manuscript.