Leray's Theorem is a fundamental result in the field of algebraic topology, particularly concerning the study of sheaf cohomology. It provides a way to compute the cohomology groups of a topological space by relating them to the cohomology of a covering space. This theorem is especially useful when dealing with complex spaces that can be decomposed into simpler pieces. The theorem states that if a topological space can be covered by open sets, the cohomology of the entire space can be derived from the cohomology of these open sets. This allows mathematicians to analyze intricate spaces by breaking them down into manageable components, facilitating deeper insights into their structure.