Since the first edition of this book in 1967, interest in sarcoidosis has increased world-wide, leading to increasing numbers of published clinical, epidemiological and laboratory studies, notably in immunology and in the pathogenesis of granulomatous inflammation. Aseries of international con ferences which started as an informal gathering in London in. 1958 has continued at approximately three-yearly intervals with increasing numbers of participants and more formal organisation, and the proceedings of all but the first have been published. When the preparation of a second edition was suggested to me, I consi dered several questions. ls there still a piace for a comprehensive, clinically orientated book on sarcoidosis? Although the reports of the international conferences bring together research reports and some reviews of topics of contemporary interest, they are useful principally to specialists in the sub ject; and, like the original papers scattered through many journals, are not convenient sources of reference for clinicians. Continued enquiries about the availability of the first edition long after it had gone out of print suggested that it had provided such a source. I therefore concluded that a second edition should be prepared, and then had to consider whether, as a physician retired from academic and hospital appointments, I was the right person to undertake the major task of incorporating in it the still-relevant parts of the first edition, the considerable amount of new information that had accumulated since 1967, and a conspectus of current studies.