A translation by Ronald Bathgate of Dr Roozeboom's 'Heterogeneous equilibria in the light of the phase theory, vol. 1: phase theory, systems of one component', 297 pages. A foreword explains that 'the object of this book is to give an overall picture of the present state of knowledge of equilibria in heterogeneous systems'. There is a contents page at the beginning, and a subject index at the end, which is followed by photocopied chapters in German taken from various published sources. The collection is accompanied by a letter from A.E.B. Owen, Cambridge University Library, to Dr R.H. Bathgate, Communication Services, Eindhoven, 20 March 1974, agreeing to accept the translation.