Wikipedia: "Shlomo Zvi Sternberg (born 1936), is an American mathematician known for his work in geometry, particularly symplectic geometry and Lie theory."


FREE reading material:

Theory of Functions of a Real Variable
https://people.math.harvard.edu/~shlomo/docs/Real_Variables.pdf

Advanced Calculus
https://people.math.harvard.edu/~shlomo/docs/Advanced_Calculus.pdf

Dynamical Systems
https://people.math.harvard.edu/~shlomo/docs/dynamical_systems.pdf

Lie Algebras
https://people.math.harvard.edu/~shlomo/docs/lie_algebras.pdf

Semi-Riemannian Geometry
https://people.math.harvard.edu/~shlomo/docs/semi_riemannian_geometry.pdf

Semi-Classical Analysis
https://people.math.harvard.edu/~shlomo/docs/Semi_Classical_Analysis_Start.pdf