In 1939–1946 he served as president of the Texas State Historical Association. During his tenure as president, he launched a project to produce an encyclopedia of Texas, which was subsequently published in 1952 as the "Handbook of Texas". The world wide web version of the work is a popular Internet reference tool on the state. In all, Webb wrote or edited more than 20 books. One of them, "The Texas Rangers" (1935) was considered the definitive study of the legendary Texas Rangers and its Captain Bill McDonald.