A topic for a Solvay Conference should be general enough to conform with the great tradition of previous conferences. On the other hand it should not be so broad that it can not be covered during the limited time of the conference. After discussion of several such topics, "Design and Synthesis of Organic Molecules Based on Molecular Recognition" was chosen. According to Albert Einstein we live in an era of perfect methods and confused aims. For example in organic chemistry the known synthetic methods allow us to prepare an astronomical number of compounds; the gap between the possible and the...