Walter Blum

This is the final volume of Heisenberg's Collected Works. It contains his papers on a (nonlinear) unified theory of elementary particles, as well as his contribution to superconductivity and multiparticle production. Especially interesting is the first group of papers, which is split intotwo sections dealing with, firstly, the formulation of the famous nonlinear spinor equation and, secondly,its applications. Among others the reader willfind a thorough discussion of Heisenberg's collaboration with W. Pauli on these matters. Illuminating annotations to the various sections in this volume have been provided by H. Koppe, R. Hagedorn and the editors.

Werner Heisenberg is one of the greatest scientists of our century. His work extends over a period of fifty years, ranging from turbulence theory, the establishment of quantum mechanics, its fundamental applications in atomic and solid state physics, to the theory of cosmic ray phenomena and of elementary particles. He recognized early the epistemological significance of the new discoveries. He was able to place the radical changes in the foundation of physics of this century in the historical context of natural philosophy. His thoughts on language as the medium to grasp scientific truth, artistic truth, religious truth, truth in general, reached many auditors and readers, scientists as well as non-scientists. In the 75 years of his life the political and social structure of his home country, of Europe and the world over underwent drastic changes. He grew up in Imperial Germany, made his great contributions to quantum mechanics during the period of the Weimar Republic and was engaged in nuclear physics when the potentates of the Third Reich tried to discredit relativity and quantum theory as "degenerate" science; in World War II he participated in the German effort to develop a nuclear reactor. After the war, he devoted himself mainly to the physics of elementary particles. In addition, he acted in many official capacities: for the promotion of research, the reconstruction of science in the Federal Republic of Germany, and the advancement of international collabora- tion.

A drift chamber is an apparatus for measuring the space coordinates of the trajectory of a charged particle. This is achieved by detecting the ionization electrons produced by the charged particle in the gas of the chamber and by measuring their drift times and arrival positions on sensitive electrodes. When the multiwire proportional chamber, or ‘Charpak chamber’ as we used to call it, was introduced in 1968, its authors had already noted that the time of a signal could be useful for a coordinate determination, and rst studies with a drift ch- ber were made by Bressani, Charpak, Rahm and Zupanci c in 1969. When the rst operational drift-chamber system with electric circuitry and readout was built by Walenta, Heintze and Schurlein ¨ in 1971, a new instrument for particle experiments had appeared. A broad study of the behaviour of drifting electrons in gases began in laboratories where there was interest in the detection of particles.

A drift chamber is an apparatus for measuring the space coordinates of the trajectory of a charged particle. This is achieved by detecting the ionization electrons produced by the charged particle in the gas of the chamber and by measuring their drift times and arrival positions on sensitive electrodes. When the multiwire proportional chamber, or ‘Charpak chamber’ as we used to call it, was introduced in 1968, its authors had already noted that the time of a signal could be useful for a coordinate determination, and rst studies with a drift ch- ber were made by Bressani, Charpak, Rahm and Zupanci c in 1969. When the rst operational drift-chamber system with electric circuitry and readout was built by Walenta, Heintze and Schurlein ¨ in 1971, a new instrument for particle experiments had appeared. A broad study of the behaviour of drifting electrons in gases began in laboratories where there was interest in the detection of particles.