From May 3-7,1997, the NATO Advanced Research Workshop on 'Biological Electron Transfer Chains' was organized in Tomar, Portugal. In the application for support the choice of the topic was justified as follows: "[Until recently efforts] have concentrated on the study of the structure and function of individual redox enzymes and proteins. Enough information is now available to make a start with the study of biological electron transfer (E1) at the next higher level of organization, that of the complete ET chain." The interest in the workshop was high: the majority of participants had...