Integral equations are extremely important in the modelling of real-world problems. These equations are at the heart of the understanding of the dynamics of many systems and play a key role in the development of theoretical tools for the study of them. Integral equations, in particular, are central to the theory of existence and uniqueness of solutions, i.e., the problem is well posed and the solution can be meaningfully defined. Additionally, their theory is at the heart of numerical analysis, being central to the design and theoretical analysis of computational methods for approximating solutions.