Martinus J.G. Veltman held his Nobel Lecture on 8 December 1999, at Aula Magna, Stockholm University.

Summary: Starting with the photon as an example of an elementary particle, Veltman continues to discuss how elementary particles can be made and studied: made at accelerators and studied with instruments like bubble chambers and spark chambers. The CERN laboratory is described. Feynman rules are illustrated for interactions involving photons and electrons. The lecture ends with a discussion of the weak interaction with the production of the new particles, the heavy bosons W and Z.