This book is indexed in Chemical Abstracts ServiceEver since 1911, the Solvay Conferences have shaped modern physics. The format is quite different from other conferences as the emphasis is placed on discussion. The 27th edition held in October 2017 in Brussels and chaired by Boris Shraiman continued this tradition and addressed some of the most pressing open questions in the fields of biophysics, gathering many of the leading figures working on a wide variety of profound problems.The proceedings contain the 'rapporteur talks' giving a broad overview with unique insights by distinguished renowned scientists. These lectures cover the five sessions: 'Intra-cellular Structure and Dynamics', 'Cell Behavior and Control', 'Inter-cellular Interactions and Patterns', 'Morphogenesis', 'Evolutionary dynamics'.In the Solvay tradition, the proceedings also include the prepared comments to the rapporteur talks. The discussions among the participants -- expert, yet lively and sometimes contentious -- have been edited to retain their flavor and are reproduced in full. The reader is taken on a breathtaking ride through a fascinating field which is expanding rapidly and which was for the first time the subject of a Solvay Conference on Physics.