Like G. Collins, the subject of my last post, William Book only did two signed covers for early Harlequin, both in 1953. And like Collins there is little to be found about Mr Book other than he was a mid century commercial artist who did illustrations for Canadian magazines and newspapers and lived in Hamilton, Ontario.
One of the 22 identifiable artists on early (first 500 issues - 1949 to 1960) Harequin books is G. Collins. Who is he/she? Possibly Gordon Collins, Ontario College of Art 1944 graduate in Commercial Art. Otherwise no information found.