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.

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.

Auf der Hamburger Tagung der Gesellschaft Deutscher Naturforscher und A.rzte im September 1956 wurde folgendes Preisausschreiben bekannt- gegeben: "Der Vorstand der Gesellschaft Deutscher Naturforscher und Arzte hat beschlossen, von Zeit zu Zeit ein Preisausschreiben zu veranstalten, das die Aufmerksamkeit lenken soIl auf bestimmte naturwissenschaft- liche oder medizinische Probleme, die im jeweiligen Zeitpunkt eine be- sondere Behandlung verlangen. In diesem Jahr ist ein Preis von DM 7000.-ausgesetzt fUr die Be- handlung des Themas ,Die Entstehung von Sternen durch Konden- sa tion diffuser Ma terie' . Dabei wird eine Darstellung der verschiedenen gegenwartig in der Literatur vorhandenen Ansatze und Theorien, nicht die einseitige Pro- pagierung einer bestimmten Theorie, gewtinscht. 1m einzelnen ist folgendes zu sagen: A. Die Preisschrift soIl eine zusammenfassende und kritische Ober- sicht geben tiber 1. die Grtinde flir die Annahme a) daB bestimmten Sterngruppen ein definiertes Alter zugeschrieben werden muB, b) daB gegenwartig Sterne aus interstellarer Materie entstehen; 2. die in der Literatur vorhandenen Ansatze zu einer physikalischen Theorie der Entstehung von Stern en und Sterngruppen durch Konden- sation interstellarer Materie, 3. die Versuche a) das FarbenheIligkeitsdiagramm verschiedener Sterngruppen, b) die raumliche Verteilung und die Geschwindigkeitsverteilung der Sterne von verschiedenem Typus und verschiedener ,Population' theoretisch zu verstehen. B. Es bleibt den Bewerbern iiberlassen zu entscheiden, wieweit sie 1. die Aufsammlung von Materie durch bestehende Sterne, 2. die Entstehung von Doppelsternen und mehrfachen Sternsystemen oder andere ihnen notwendig erscheinende Fragenkomplexe in die Dar- stellung hineinziehen wollen.