  Poisson algebras have become an essential topic in mathematics with a rich
structure and wide applicability. Despite numerous resources available on
Poisson structures, the algebraic side of the story remains relatively less
explored. This paper presents an extended version of a mini-course given during
the virtual Winter School and Workshop "Wisla 20-21." The course covers various
aspects of Poisson algebras, focusing on both algebraic and geometric
perspectives. While most of the lectures cover established results, the final
chapter includes recent classification results on "low rank" double quadratic
Poisson brackets.
