Georges KAhler was one of the most prominent German scientists of recent history. In 1984, at an age of 38, he received the Nobel Prize in Physiology or Medicine, together with N.K. Jerne and C. Milstein, for inventing the technique for generating monoclonal antibodies. This method and its subsequent applications had an enormous impact on basic research, medicine and the biotech industry. In the same year, KAhler became one of the directors of the Max-Planck-Institute of Immunobiology in Freiburg; his unfortunate premature death in 1995 set an end to his extraordinary career. Prof. Klaus Eichmann, who had invited KAhler to become his codirector, is one of the people who were closest to him.

This scientific biography commemorates the 10th anniversary of KAhler's untimely death. KAhler's scientific achievements are explained in a way to make them understandable for the general public and discussed in the historical context of immunological research.

The network paradigm dominated immunological research from the early 1970s to the late 1980s. The originator, Niels Jerne, hypothesized that the vast diversity of antibodies in each individual forms a network of mutual "idiotypic" recognition, thus regulating the immune system. In context of emerging concepts of systems biology such as cybernetics and autopoesis, the "Eigenbehavior" of the immune system fascinated an entire generation of young immunologists. But fascination led to experimental errors and overinterpretation, eventually magnifying the immune system from a mere infection-fighting device to a substrate of personality and individuality. As a result, what initially appeared as an exciting new perspective of the immune system is now viewed as a scientific vagary, and is largely abandoned. The author, himself a participant in the network vagary, begins with a description of the leading theoretical concepts on fact finding in science. This is followed by a historical account of the rise and fall of the network paradigm, complemented by personal interviews with some of the prominent protagonists. By comparing the network paradigm to other, more lasting concepts in life science, the author develops a general perspective on how solid knowledge is derived from error-prone scientific methodology, namely by exposure of scientific notions to the scrutiny of reality.

On December 6, 1961, a contract was signed by which the research institute of the Wander AG in Freiburg became the Max-Planck-Institut fUr Immunbiologie. The transfer of ownership took place during a happy expansion phase of the Max-Planck Society in which a growing economy in Germany allowed the foundation of many new research institutes by the Max-Planck-Society and other organizations. Nevertheless, it was a remarkable event. The acquisition by an academic organization of an institute formerly operated by an industrial company was rather unusual, not to speak ofthe fact that not only the facilities but also the entire scientific personnel were taken over. Retrospectively, the 40 years of the institute in the Max-Planck Society can be divided into 2 very different phases of 20 years each. The first 20 years were characterized by a continuation of the research that had begun in the Wander institute and centered on the structure and function of the bacterial compound endotoxin. During the second 20 years, the institute more than doubled in size and developed into an interdisciplinary research center that focuses on the development and organization of multicellular systems by combining studies in two fields of research: immunology and developmental biology. th The 40 anniversary of the foundation of the Max-Planck-Institute was celebrated by a ceremony including a scientific symposium. The first part of this volume presents the lectures given at the symposium by six leading biologists."