Modified gravity models play an important role in contemporary
theoretical cosmology. The present book proposes a novel approach to the
topic based on techniques from noncommutative geometry, especially the
spectral action functional as a gravity model. The book discusses
applications to early universe models and slow-roll inflation models, to
the problem of cosmic topology, to non-isotropic cosmologies like
mixmaster universes and Bianchi IX gravitational instantons, and to
multifractal structures in cosmology.
Relations between noncommutative and algebro-geometric methods in
cosmology is also discussed, including the occurrence of motives,
periods, and modular forms in spectral models of gravity.