George Reed Sill Jr. contributed to the Photo-Lettering library. In different Photo-Lettering books he is shown on the contributor list either as “G. Reed Sill Jr.” or, later, simply as “G. Reed Sill”.
“Son of Mr. and Mrs. G. Reed Sill […] Graduated from Pratt Institute in 1939 and was engaged in commercial art before entering the [military …]. Upon his discharge […] he returned to his work in the field of commercial lettering” [Source]