During viral assembly, genome molecules are packaged by capsid proteins. A well-known example is the insertion of viral DNA molecules by a molecular motor into the capsid of bacteriophage viruses under conditions far from thermodynamic equilibrium. The talk will discuss the packaging of large single-stranded RNA molecules under conditions that are close to thermodynamic equilibrium. Experiments on the equilibrium packaging of RNA can be analyzed by borrowing simple concepts from polymer physics, aqueous electrostatics, and the theory of phase transitions. In the second part of the talk, I will focus on the assembly and disassembly of the human HIV-1 virus.