  First-principles calculations of multi-hadron dynamics are a crucial goal in
lattice QCD. Significant progress has been achieved in developing,
implementing, and applying theoretical tools that connect finite-volume
quantities to their infinite-volume counterparts. Here, I review some recent
theoretical developments and numerical results regarding multi-particle
quantities in a finite volume. These results include $N\pi$ scattering, systems
of two and three mesons at maximal isospin, three-body resonances in a toy
model, and the formulation of effective theories in finite volume for
multi-nucleon systems.
