[en] Cross sections for neutron interaction with ⁴⁰Ca, with emphasis on production of gamma rays, are calculated and compared with experiment. Various nuclear models are applied judiciously for the calculation. The Hauser-Feshbach theory for binary reactions is here extended to include tertiary reactions, which are important for ⁴⁰Ca from 10 to 20 MeV. To conserve angular momentum, we included continuum-level spins and parities in the gamma-ray-production calculation. An extensive measurement of gamma-ray-production cross sections, which became available after all model parameters were fixed, confirms the predictability of the models, particularly in the high-energy range, where tertiary reactions contribute significantly. Recommended values of the total neutron cross section are presented graphically in detail and other cross sections in overview