In this third volume of Bertram Kostant's collected papers, the reader will engage in Works published between 1978 and 1990 of one of the major architects of modern Lie theory. Virtually all his papers are pioneering with deep consequences, many giving rise to whole new fields of activities. His interests span a tremendous range of Lie theory, from differential geometry to representation theory, abstract algebra, and mathematical physics. Some specific topics cover algebraic groups and invariant theory, the geometry of homogeneous spaces, representation theory, geometric quantization and symplectic geometry, Lie algebra cohomology, Hamiltonian mechanics, modular forms, Whittaker theory, Toda lattice, and much more. It is striking to note that Lie theory (and symmetry in general) now occupies an ever increasing larger role in mathematics than it did in the fifties. Now in the sixth decade of his career, he continues to produce results of astonishing beauty and significance for which he is invited to lecture all over the world. A distinguished feature of this second volume are Kostant's commentaries and summaries of his papers in his own words in addition to commentaries from colleagues.

Kostant is an architect of modern Lie theory and his mathematics interests span a huge range

Preface.- Acknowledgements.- On Whittaker Vectors and Representation Theory.- (with Kazhdan, D. and Sternberg, S.) Hamiltonian Group Actions and Dynamical Systems of Calogero Type.- Harmonic Analysis on Graded (or Super) Lie Groups.- The Solution to a Generalized Toda Lattice and Representation Theory.- Quantization and Representation Theory.- A Lie Algebra Generalization of the Amitsur-Levitski Theorem.- Poisson Commutativity and Generalized Periodic Toda Lattice.- (with Sternberg, S.) Symplectic Projective Orbits.- Coadjoint Orbits and a New Symbol Calculus for Line Bundles.- The McKay Correspondence, The Coxeter Element and Representation Theory.- (with Kumar, S.) The Nil Hecke Ring and Cohomology of G/P for a Kac-Moody Group G.- (with Kumar, S.) The Nil Hecke Ring and Cohomology of G/P for a Kac-Moody Group G*.- (with Sternberg, S.) Symplectic Reduction, BRS Cohomology and Infinite-Dimensional Clifford Algebras.- (with Kumar, S.) T-Equivariant K-Theory of Generalized Flag Varieties.- (with Guillemin, V. and Sternberg, S.) Douglas' Solution of the Plateau Problem.- The Principle of Triality and a Distinguished Unitary Representation of SO(4,4).- (with Sternberg, S.) The Schwartzian Derivative and the Conformal Geometry of the Lorentz Hyperboloid.- (with Kumar, S.) T-Equivariant K-Theory of Generalized Flag Varieties.- A Formula of Gauss-Kummer and the Trace of Certain Intertwining Operators.- The Vanishing of Scalar Curvature and the Minimal Representation of SO(4,4).- Comments on Papers in Volume III.