Part I Overture: 1. Introduction.- 2. N-Functions.- 3. Musielak-Orlicz Spaces.- Part II PDEs: 4. Weak Solutions.- 5. Renormalized Solutions.- 6. Homogenization of Elliptic Boundary Value Problems.- 7. Non-Newtonian Fluids.- Part III Auxiliaries: 8. Basics.- 9. Functional Inequalities.- References.- List of Symbols.- Index.