The editors are very pleased to be able to celebrate the 70th birthday of Daan Frenkel (Figure 1) with this Special Issue of Molecular Physics. The large number and the quality of the scientific contributions, accompanied by heartfelt acknowledgements to Daan, reflect his influence on a very broad field ranging across fundamental statistical thermodynamics, computer simulation, and phase transitions. Moreover, these attest to his continuing influence on current practitioners. This is testament to the enormous respect and admiration in which Daan is held, not only for his seminal and world-leading scientific publications, but also as a true gentleman of science, friend, and colleague.