the observer’s handbook for 1977 is the sixty-ninth edition. There are some changes and additions: the presentation of the configurations of Jupiter’s satellites, and of the sun’s selenographic colongitude, is different (see pg. 34); a diagram showing twilight and sidereal time has been added (pg. 12); the section on “Planets” has been rewritten and extended; and some “Suggestions for Further Reading” have been added. The index is now on the last page.

the observer’s handbook for 1976 is the sixty-eighth edition. I wish to thank all those who assisted in its preparation: those whose names appear in the various sections, those mentioned below, and especially my editorial assistant, John F. A. Perkins.

the observer’s handbook for 1975 is the sixty-seventh edition. I wish to thank all those who assisted in its preparation: those whose names appear in the various sec­ tions, those mentioned below, and especially my editorial assistant John F. A. Perkins.

the observer’s handbook for 1974 is the sixty-sixth edition. I wish to thank all those who assisted in its preparation: those whose names appear in the various sections, and my assistant editor Marie Fidler Litchinsky. Special thanks go to Margaret W. Mayall, Director of the A.A.V.S.O., for the predictions of Algol and of the variable stars, to Leslie V. Morrison and Gordon E.

the observer’s handbook for 1973 is the sixty-fifth edition. The major change in this edition is the inclusion of data on grazing occultations over Canada. These data were supplied by Mr. L. V. Morrison of the British Nautical Almanac Office.

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.