Wolfgang Ketterle held his Nobel Lecture December 8, 2001, at Aula Magna, Stockholm University. He was presented by Professor Mats Jonson, Chairman of the Nobel Committee for Physics.

Summary: Starting by comparing Bose-Einstein condensates (BEC) with laser light, the experimental challenges to make and observe BEC in gases are discussed. BEC was eventually achieved by combining laser cooling and evaporated cooling methods. The first observation of a phase transition to BEC in sodium in 1995 was followed by studies of BECs that are cold condensates of atoms that interact and are coherent. The formation of vortices and matter waves are discussed, as is the notion that BECs should be regarded both as a tool for knowledge and a tool for applications.