the observer’s handbook for 1971 is the 63rd edition. A number of small changes and additions have been made in response to suggestions from readers; further changes and additions are contemplated for the 1972 edition. Additional informa­tion about the planet Mars is included, in view of the favourable opposition which occurs in 1971.

Cordial thanks are offered to all those who assisted in the preparation of this edi­tion to those whose names appear in the various sections and to Marie Fidler, Edward Kipp, Roslyn Shemilt, Maude Towne and Isabel Williamson. Special thanks go to Donald Davis, for providing a new cover design, to Margaret W. Mayall, Director of the A.A.V.S.O., for the predictions of Algol and the variable stars, to Gordon E. Taylor for the prediction of planetary appulses and occultations, and to Malcolm M. Thomson and the Department of Energy, Mines and Resources, for providing a map of time zones. My deep indebtedness to the British Nautical Almanac Office and to the American Ephemeris is gratefully acknowledged. Finally, as only the third editor of the handbook in 63 years, I wish to record my sincere gratitude to the late Miss Ruth Northcott for her inspiration and for the high editorial standards which she established.

John R. Percy