This book on active control of concrete properties presents the work of the RILEM TC 317-ACP and provides a scientific framework for further developments and industry implementations of these technologies. Active control of properties of cementitious materials refers to the action or intervention for controlling specific properties (e.g. rheology, stiffening) by applying an external trigger signal that induces a response in the cementitious material, with a modification of properties or behaviour as a result. Some historical methodologies that could be considered as active control avant la lettre have been summarized in chapter 1. They can be based on different types of intervention: mechanical, chemical, thermal, hygral, pressure, magnetic, electric, microwave. In more recent approaches, the active control mechanism is providing extra opportunities by the addition of responsible polymers or particles to the concrete mix design, that can be triggered by an external signal. Control of properties can in first instance be related to rheology, setting, and shrinkage. The literature regarding active control of those properties has been synthesized and summarized in chapters 3 (rheology), 4 (setting) and 5 (shrinkage). Some processes offer very good opportunities for the application of active control methodologies. For some very relevant processes, available literature information has been summarized in chapters 6 (pumping), 7 (formwork casting), 8 (3D concrete printing) and 9 (slabs and roads).