Invariant Theory is a branch of mathematics that studies properties of objects that remain unchanged under certain transformations. It primarily focuses on polynomial functions and their symmetries, particularly in relation to groups of transformations. This theory has applications in various fields, including geometry and physics. One of the key figures in the development of Invariant Theory is David Hilbert, who contributed significantly to the understanding of invariants in the early 20th century. The theory also intersects with algebraic geometry and representation theory, providing tools to analyze and classify mathematical structures based on their invariant properties.