He served in the Army Air Force in the South Pacific during World War II.
In 1949, he joined E. Ross Allen's Reptile Institute in Silver Springs, Florida, as Research Director.
Neill was the first to describe the Everglades rat snake (Elaphe obsoleta rossalleni, a subspecies of Elaphe obsoleta, 1949), the Gulf hammock dwarf siren (Pseudobranchus striatus lustricolus, a subspecies of Pseudobranchus striatus, 1951), the one-toed amphiuma (Amphiuma pholeter, 1964), and the southern Florida rainbow snake (Farancia erytrogramma seminola, a subspecies of Farancia erytrogramma, 1964).
Similarly, a subspecies of pygmy snail-eating snake, Sibon sanniolus neilli, was named in his honor by Henderson, Hoevers, and Wilson in 1977.
The book and photos tell the history and culture of these people and includes two excellent drawings by the author.