Book excerpt: The word ‘fluid’ describes a phenomenon as well as a material property. Of special interest is how aspects of fluidity influence the active and direct handling of materials and how its special characteristics are expressed in experimental practices and thinking patterns. The motivation for focusing on fluidity as a prerequisite for ‘becoming’ and the nature of processes originated from the art-based ‘Liquid Things’ research project. As this subject covers a very wide spectrum, the approach was modified to allow the participation of several disciplines; the book draws on the philosophy of science, hydrodynamics, and the cultural sciences, and focuses on the role of fluidity in cognitive and experience processes with the aim of establishing a grammar of ‘movable’ materials.