CONCEPT - The COsmological $N$-body CodE in PyThon

CO$N$CEPT (COsmological $N$-body CodE in PyThon) is a free and open-source code for cosmological $N$-body simulations on massively parallel computers with distributed memory. Collisionless dark matter is the only implemented particle species. Gravity can be computed using the PP, PM or the P$^{3}$M algorithm. The goal of CO$N$CEPT is to make it pleasant to work with cosmological $N$-body simulations - for the cosmologist as well as for the source code developer. This is the user guide. The source code and additional documentation can be found at https://github.com/jmd-dk/concept/