had recognized the need for improved international cooperation in optics, had sketched a charter for ICO, and had planned a comprehensive program for the ICO initial meeting in 1948. The First Congress, ICO-1, Delft, Netherlands, 1948 The first official meeting of ICO took place 12–17 July 1948 at the Physics Laboratory of the Technische Hogeschool, Delft, Netherlands. Forty-four delegates from eleven countries attended the meetings. At the first session Prof Fleury announced that IUPAP had cordially accepted the affiliation of ICO and had approved the Statutes provisionally adopted at Prague. The appointment of officers elected in 1947 was confirmed, and two additional vice-presidents were elected: S.S. Ballard (USA) and A.C.S. van Heel (Netherlands). Thus the eleven countries represented at Delft became the founding member countries of the ICO; Belgium, Czechoslovakia, France, Great Britain, Italy, Netherlands, Poland, Spain, Sweden, Switzerland, and the United States. In addition to the sessions devoted to reports on the problem areas that had been assigned at Prague, the participants heard four invited lectures: by M. Françon (France); T. Smith (Great Britain); D.B. Judd (USA); and A.C.S. van Heel (Netherlands). On the first day of the meeting Prof van Heel hosted a reception at his home, and on the last evening the group held a formal dinner. During the week there were several local visits to research laboratories: de Oude Delft; the Kammerlingh-Onnes Laboratory in Leiden; the Philips Research Labs at Eindhoven; van Cittert's collection of historical optical instruments at Utrecht; and the optics and electron optics laboratories of the Technische Hogeschool, Delft. This sort of mixing of technical reports and social activities is important in building a sense of community among the attendees. The principal work at the meeting was the presentation of detailed reports on the topics that had been assigned at Prague. These reports occupied most of the six technical sessions. The delegates also agreed that ICO should not act as a vehicle for publishing original research papers. Full use should be made of existing scientific journals..The delegates agreed that one of the roles of ICO should be to sponsor conferences at which sets of invited papers are given on some specialized field or fields of optics. At the final session President Thomas Smith announced that he had been authorized to invite the ICO to hold the next meeting in 1950 in London. This announcement was accepted by acclamation. The Congresses of the International