This book describes in two volumes the emergence and further development of the concept of 'molecule' in the sciences and so against the background of Epicurus' neoatomism as voiced by Lucretius. 'Sciences' is here taken in the broad sense, that is: to comprise not only the exact sciences and the life sciences, but also mathematics and (natural) philosophy.

As it happened the molecular theory came up in the Netherlands. It was invented by the natural philosopher and medicinae doctor Isaac Beeckman (1588-1637). Beeckman, a close friend of René Descartes, developed a 'discrete' picture of the world, in which the molecular theory featured prominently, together with a taylor-made mathematics. At the end of the XVIIIth century the molecular theory had grown into molecularism, a real Theory of Everything. Indeed, both XIXth century physics and chemistry appear to be essentially molecular sciences.

The second volume addresses in the first chapters the development of biology and medicine and of crystallography and mineralogy during the XIXth century. In this period biology lived its emancipation as a life science sui generis, while crystallography branched off from mineralogy. A separate chapter deals with the rise of a uniform system of units, the so-called Système international des unités, with particular attention for the molecular aspects. Up until 1925-1940 the developments in the various domains are analyzed in detail. For the later period the course of events is only sketched in using 12 Nobel Prizes as beacons. The last chapter, then, concerns an epilog in which the book's theme is reconsidered from a systematic point of view on the basis of the principal novel insights. The second volume concludes with a bibliography and indexes of names and subjects. The main tenet of the book is that a new picture of the world has emerged, a picture that, in the spirit of Galileo and Huygens, was called after the House Orange.