This volume is a collection of the Nobel lectures delivered by the prizewinners, together with their biographies and the presentation speeches for the period 2001 - 2005. Each Nobel lecture is based on the work for which the laureate was awarded the prize. This volume of inspiring lectures by outstanding physicists should be on the bookshelf of every keen student, teacher and professor of physics as well as of those in related fields.Below is a list of the prizewinners during the period 2001 - 2005 with a description of the works which won them their prizes.(2001) Eric A Cornell, Wolfgang Ketterle undefined (2002) Raymond Davis Jr, Masatoshi Koshiba - for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos undefined (2003) Alexei A Abrikosov, Vitaly L Ginzburg undefined (2004) David J Gross, H David Politzer undefined (2005) Roy J Glauber, John L Hall & Theodor W Hansch - for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique.