FROM THE PREFACE This book addresses problems and solutions of formulation and preformulation with which I have concerned myself for 34 years. When I was employed in the pharmaceutical industry I worked at functions, in the 1960's, which were the precursors of preformulation, and my early publications dealt with such matters. In the following decades advances have been made in methodology and the realm of preformulation has grown. Theory and the way in which problems are viewed have also undergone change. The text deals with the pharmaceutical aspects of preformulation, not the synthetic nor the analytical aspects. It takes its vantage point at the point in time when the pharmaceutical preformulator first obtains a sample of the drug substance, and it explores the physical, chemical and technological aspects that are needed for a full exploration of the potential advantages and disadvantages of the drug substance. It is only through the understanding of underlying principles that adequate exploration can be carried out.