This catalogue brings together three independent exhibitions at the Museum Boijmans van Beuningen in Rotterdam, The Netherlands; Malmö Konsthall& Lunds Konsthall, Sweden; and Hara Museum of Contemporary Art, Tokyo, Japan, in 2005–2006. Compiled by Michael Heimann, the publication investigates reality as a constant flow of actions or causes and effects. The focal themes are Eliasson’s experiments with light and colour perception, the causal relation between individuals and their surroundings, studies of sound waves, and the visualisation in two and three dimensions of acoustic waves. With contributions from Daniel Birnbaum, Ina Blom, Italo Calvino, Olafur Eliasson, Mark Wigley, and Ludwig Wittgenstein the textual matter ranges from topics such as vibrations and waves to personal engagement and research into the colour white. The book includes installation views of all three exhibitions as well as older Eliasson works related to the theme. These are combined with photographs of experiments and work development at Studio Olafur Eliasson.