According to the textbook "Network Science" by Albert-László Barabási, percolation theory is a specialized branch of both mathematics and physics . It involves node clustering in a network that is randomly added to in different stages. I have studied percolation theory before, and the citation I have provided is from the textbook I have used for one of my classes. However, I am still unaware of the origins of percolation theory, specifically about how it was developed. Furthermore, does anyone know who has contributed to the theory, or who first studied it? If there are any sources or documents that are available, please post an answer below. Thank you for your help in advance.