Explore the fundamental concepts of entropy in soft matter self-assembly through this comprehensive lecture by Francesco Sciortino at the International Centre for Theoretical Sciences. Delve into topics such as translational and rotational entropy, phase transitions in hard sphere systems, the isotropic-nematic transition, and entropy calculations in fluids. Examine the role of entropy in crystal selection, predictive self-assembly of polyhedra, and depletion interactions. Discover how entropy influences the stability of various phases and structures in colloidal systems, including DNA-coated patchy colloids and lock-and-key particles. Gain insights into cutting-edge research on shape-dependent colloidal separations and surface roughness-directed self-assembly, providing a deep understanding of entropy's crucial role in soft matter phenomena.