Computation is a national and international network of computational scientists with diverse and complementary backgrounds ranging from quantum chemistry to statistical mechanics and coarse-grained models. The main mission of Computation is to develop innovative multiscale methods and algorithms to tackle a wide range of scientific challenges. This strategy is built on the traditional strong position of Italy in computational-modelling science: it was one of the birthplaces of this key scientific discipline, giving rise to the school that educated many of the current scientific leaders in computation. Multiscale modelling has proven to be powerful in many theoretical and applied fields, including Biology, Chemistry, Physics, Mathematics, and Engineering. The approach allows detailed investigations of complex phenomena by combining highly accurate methods to study the system at the level of the detailed physical process with less costly methods to treat the remaining model system. With this dual-pronged approaches, the models can reach huge dimensions, up to millions of particles. Multiscale approaches and methods are important frontiers in computational science, and are at the heart of Computation.