This book was originally published as a doctoral thesis and was de-
fended by the author at the Tilburg School of Economics in 1969. It has
the characteristics of a work on industrial econometrics. On the one
hand relevant economical, statistical and mathematical theory is treated
and on the other a model for a very actual situation has been created
and utilised to solve a practical problem. The selection from current
reference material always has a personal tinge of course, and other
theoreticians will find some of the author's departures from the theme a
little unnecessary. However, if the theory propounded in this book is
tested for its relevance in solving practical problems, the selection
may be regarded as a success. Thanks to the way in which the case is
developed the book is of great practical use. So often in writings on
operations research theory is applied to so-called practical examples,
which in fact can only be des- cribed as five finger exercises. It is
clear from the early chapters that the author has struggled with this
problem but that he has found a solution. And in his concluding remarks
he indicates briefly how this case can be incbrporated in a context
which goes beyond short-term optimisation. In the description of the
preparatory and implementation phases the author shows how a clash
between practical implementation and theoretical application can
successfully be avoided in this preparatory work.