This volume contains the proceedings of the Ninth Meeting of the "International Study Group for Tryptophan Research" (lSTRY), held at the University of Hamburg, Germany, from October 10 to 14, 1998. At this meeting the recent developments in the field of tryptophan research were presented by leading researchers from all over the world in 81 oral and 48 poster contri- butions. Research on tryptophan and its derivatives provides an inexhaustible subject. At the conference we tried to compose a multifacetted picture of the recent investiga- tions through contributions from the major disciplines...

English summary: The human brain is much more flexible than hitherto thought. The way brain cells are used strongly influences how neurons connect with each other. Since little boys, teenagers and later adult representatives of the male sex take an interest in things so different from their female counterparts, it is obvious that male brains must develop differently. If males would use their brains accordingly, they could become more powerful. German description: Wie wird ein Mann ein Mann? Oder etwas praziser: Wie wird aus dem, was ein Mann werden konnte, schliealich das, wofur sich der...

The picture on the following page is being reproduced here, at the request of the partici pants in the Advanced Research Workshop "Amino Acid Availability and Brain Function in Health and Disease." I displayed this limewood carving, entitled "Neurochemistry," during my closing remarks to this extraordinarily stimulating and productive workshop so ably organized by my collaborator Dr. Gerald Huether. We scientists need two sturdy legs to carry us through all the twists and turns of our academic careers. We should also have, as it were, a reserve leg handy, to help us stay upright when this...

This volume contains the proceedings of the Ninth Meeting of the "International Study Group for Tryptophan Research" (lSTRY), held at the University of Hamburg, Germany, from October 10 to 14, 1998. At this meeting the recent developments in the field of tryptophan research were presented by leading researchers from all over the world in 81 oral and 48 poster contri- butions. Research on tryptophan and its derivatives provides an inexhaustible subject. At the conference we tried to compose a multifacetted picture of the recent investiga- tions through contributions from the major disciplines...