Integration Theory is a mathematical framework that focuses on the process of finding integrals, which are fundamental in calculus. It involves determining the area under curves, solving differential equations, and understanding the accumulation of quantities. The theory is essential for various applications in physics, engineering, and economics. In addition to its mathematical significance, Integration Theory also plays a crucial role in fields like probability theory and functional analysis. It helps in understanding concepts such as Lebesgue integration, which extends traditional integration methods, allowing for more complex functions and spaces to be analyzed effectively.