During the past 40 years many patents and articles have been published which describe methods and materials for water vapor permeable materials. These materials were primarily designed to substitute leather in its look and per­ formance. Later other industrial applications were found where microporosity or water vapor permeability could be used. The aim of this book is to give a survey of this matter, describing in an abridged way all the publications existing up to 1996. The terms "water vapor permeable material", "artifiGialleather", "synthetic leather", "leather substitute" or "man-made leather" are defined, and the special characteristics of leather are compared with its substitutes. Then the special methods used to produce microporous and hydrophilic materials, suitable substrates, end uses in fields other than wearing purposes, testing methods, as well as patent strategies and ecological behavior are discussed. Each chapter starts with general remarks about the the specific characteris­ tics of its motto; then published examples belonging to the subjects of the chap­ ter are described. Sources of most of the literature have been the "Textilbericht" and the of Bayer AG - today no longer in existence. Addi­ "Hochmolekularbericht" tionally, Chemical Abstracts and original publications in the form of patents and articles in books and journals are used. During the past 40 years many patents and articles have been published which describe methods and materials for water vapor permeable materials. These materials were primarily designed to substitute leather in its look and performance.