"Version: 20200901"--Title page verso.Includes bibliographical references.1. The universe on large and small scales -- 1.1. Homogeneous and isotropic cosmology -- 1.2. Hamiltonian -- 1.3. Geometry -- 1.4. Perturbative inhomogeneity -- 1.5. Spherically symmetric models -- 1.6. Full inhomogeneity2. Covariance -- 2.1. Lagrangian and Hamiltonian formulations -- 2.2. Action principles -- 2.3. Canoniā¦