Jacobus van't Hoff proposed in 1874 that molecules have three-dimensional structures. The three-dimensional shape of molecules is responsible for many of their chemical and physical properties, such as the optical rotation of light. The cover picture illustrates a novel reaction microscope that was developed at LaserLaB Amsterdam to study and control molecular photodynamics. It employs advanced single-particle imaging detectors that measure the full three-dimensional velocity distribution of correlated electrons and (fragment) ions emitted from an excited molecule. Shaped femtosecond laser fields are used to control and manipulate the dynamics in the excited molecule in order to steer the outcome of the photochemical reaction. Recent experimental results are reviewed by M. H. M. Janssen and coworkers on p. 1459, illustrating the wealth of detailed information that can be obtained about the interplay between shaped laser fields, femtosecond dynamics, ionization processes and multichannel pathways in three-dimensional (chiral) molecules.