A capability for launching heavy payloads of scientific equipment to investigate other planets of our solar system can be anticipated within the next few years. It is to be expected that the first investigations of other planets will involve direct measurements of the atmospheres of these planets, even before scientific apparatus is landed on their surfaces. Such scientific studies, probably first of Mars and Venus, are important, not only to the investigation of the planets themselves, but may also be expected to contribute substantially to information concerning the origins of the solar system and of the Earth.For these reasons the Space Science Board of the National Academy of Sciences held a one‐day conference in June 1960 to (i) discuss the present state of knowledge of planetary atmospheres as known from ground‐based observations, (ii) consider the most important characteristics of planetary atmospheres about which additional information is needed and (iii) discuss, in a preliminary way, the experiments which should be undertaken to obtain the answers to questions raised in (