LHS 1140 is a cool M-dwarf (about 0.18 solar masses, 3,096 K, 0.22 solar radii), 15.0 light-years from Earth. LHS 1140 b is a nearby rocky super-Earth in the habitable zone and one of the best small planets for atmospheric study. LHS 1140 c is a 1.9-Earth-mass planet, with an orbital period of 3.8 days, at 0.027 AU from its star, and an equilibrium temperature near 422 K, discovered in 2018 via transit. LHS 1140 b is a 5.6-Earth-mass planet, with an orbital period of 24.7 days, at 0.095 AU from its star, and an equilibrium temperature near 226 K, discovered in 2017 via transit. Mutual gravitational tugs between the planets can slowly reshape their orbits, preserving clues to the system's assembly.