It is a great pleasure to be asked to contibute a foreword to this monograph, both as a friend and a colleague of the author, Dr Bernd Page, and as the originator of the earliest of all ref erences to health system models cited in Table 1 of Appendix 1 and Bibliographies I & II Actually, while that paper was still at press a much simpler and more practically oriented version appeared in The Lancet (31 May 1952), written jOintly by Briga dier J.D. Welch and me. The former was key member of the In vestigation into the Functions and Design of Hospitals, a pio neer research group, jOintly...

This book brings together the personal accounts and reflections of nineteen mathematical model-builders, whose specialty is probabilistic modelling. The reader may well wonder why, apart from personal interest, one should commission and edit such a collection of articles. There are, of course, many reasons, but perhaps the three most relevant are: (i) a philosophicaJ interest in conceptual models; this is an interest shared by everyone who has ever puzzled over the relationship between thought and reality; (ii) a conviction, not unsupported by empirical evidence, that probabilistic modelling...