Complex problems and ambitious goals are often thought to become easier by enlarging and diversifying the group of experts dealing with them. As a result, these complex entities are fragmented into smaller ones that can be dealt with by single laboratories. Bart Penders ventured into nutrition science to observe and join teams of scientists to find out what happens to these problems and goals. He attended conferences and workshops and worked in their laboratories. He shows that scientists mobilise everything in their power to solve problems: they reconstruct elements of the problem, such as...