In 1908 he published his only large treatise An introduction to the theory of infinite series which was based on lectures on analysis he had given at Galway. Hardy said:
Sa 1908 siya nai-publish na ang kanyang lamang malaking treatise Isang pagpapakilala sa teorya ng walang hanggan serye kung saan ay batay sa mga lektura sa analysis niya na ibinigay sa Galway. Hardy said: