Foreword

The twentieth volume of the “Digest of the Literature on Dielectrics” covers literature published during the calendar year 1956. The material was gathered by the authors mainly from engineering and scientific journals. However, many books, or pertinent chapters in books, are digested, and occasional reference is made to papers given at scientific meetings and PhD theses. The Digest is a voluminous source of reference material, and affords the researcher with a convenient means of keeping abreast of important events in both fields of special and general interest.