This twentienth volume of ABHB (Annual bibliography oj the history oj the printed book and libraries) contains 3899 records, selected from some 2000 periodicals, the list of which follows this introduction. They have been compiled by the National Committees of the following countries: Latin America Arab countries Luxembourg Australia The Netherlands Austria Norway Belgium Poland Bulgaria Portugal Canada Rumania Denmark South Africa Finland Spain France Sweden German Democratic Republic Switzerland German Federal Republic USA Great Britain USSR Hungary Yugoslavia Ireland (Republic of) Italy Latin America and the Arab countries are being covered through the good offices of American and British colleagues. Owing to unforeseen circumstances the major part of the Belgian contri­ bution will be included in volume 21. Benevolent readers are requested to signal the names of bibliographers and historians from countries not mentioned above, who would be willing to co-operate to this scheme of international bibliographic collaboration. The editor will greatly appreciate any communication on this matter. Subject As has been said in the introduction to the previous volumes, this bibliography aims at recording all books and articles of scholarly value which relate to the history of the printed book, to the history of the arts, VIII INTRODUCTION crafts, techniques and equipment, and of the economic, social and cultural environment, involved in its production, distribution, conservation, and description. Of course, the ideal of a complete coverage is nearly impossible to attain.