I've just added a new page about the different publishers identified with McGill's postcards. See the link on the navigation bar at the top of the blog just below the image and title.
Publishers are another confusing element of the McGill story. The information I have is limited in many cases. Even the few books about McGill do not have any great detail about the publishers apart from the obvious main ones - Joseph Asher & Co., Inter-Art Co. and D Constance Ltd. I intend to update the page about publishers as and when I come across anything new.
McGill is definitely known to have worked with certain publishers but his periods of freelance work are much hazier. Plus there may have been some unscrupulous publishers who printed his cards without permission. The full story may never be clear!
