Professor Zdenek Kopal is sixty-seven this year even though his scientific activity, enthusiasm and springy step hardly betray the ad­ vancement in years. He carne to Manchester as Professor of Astronomy thirty years ago after a very fruitful association of fourteen years with the Harvard Observatory. Much impressed with the young man, Harlow Shapley, who with characteristic insight had recognised in Kopal the qualities that have since made him an outstanding leader in ec1ipsing binary research, had invited him over as a Research Associate. In the subsequent decade Kopal set about the task of introducing analytical rigour in the solution of orbit al elements that hitherto had depended ex­ c1usively on the semigraphical procedures introduced by Russell and exploited fully by Shapley. These first efforts stimulated publication of the first of his many books on ec1ipsing variables; the Introductian ta the Study of Ec/ipsing Variables summarized these iterative methods and remains a c1assic in this field. Soon after the appearance of this volume in print, Kopal gave a course on this subject for the graduate students at Harvard. I was one of those who had the opportunity to attend it and learn much on the need of care and precision in the practice of photoelectric photometry and the importance of exploiting such data to the fullest extent with methods of increasing resolving power.