With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory supplemented by many concrete examples for a great variety of noncompact semisimple Lie algebras and groups. Contents:IntroductionLie Algebras and GroupsReal Semisimple Lie AlgebrasInvariant Differential OperatorsCase of the Anti-de Sitter GroupConformal Case in 4DKazhdan–Lusztig Polynomials, Subsingular Vectors, and Conditionally Invariant EquationsInvariant Differential Operators for Noncompact Lie Algebras Parabolically Related to Conformal Lie AlgebrasMultilinear Invariant Differential Operators from New Generalized Verma ModulesBibliographyAuthor IndexSubject Index