His first book A Treatise in the Differential Geometry of Curves and Surfaces, published in 1909, was on this topic and was a development of courses he had given at Princeton for several years.
Kanyang unang libro A Treatise sa kaugalian geometry ng mga kurva at ibabaw, inilathala sa 1909, ay sa paksang ito at ay isang pag-unlad ng kurso niya na ibinigay sa Princeton para sa ilang mga taon.