Adam, my editor and publisher, had made suggestions for objects that the authors could be holding that relate to their stories. Arthur Machen holds a Black Seal.
Robert Bloch, standing to the right of Machen, holds a skull and has a towel from the Bates Motel over his shoulder. Bloch is probably most known for having written the novel Psycho. I’ve never read Psycho. I tend to prefer my horror fiction to revolve around supernatural menaces rather than the horrors human beings inflict on each other.
Bloch wrote a number of “Cthulhu Mythos” stories, mostly at the beginning of his career. Given the number of horror anthologies I’ve consumed I’ve probably read more than one of them but the one that has stuck in my memory is Notebook Found in an Deserted House. I think I first read it in one of those old Alfred Hitchcock anthologies but a quick googling isn’t turning up any confirmation.
Bloch also wrote Strange Eons, a Mythos novel (if I remember correctly) about Nylarlathotep bringing about the end of the world. I didn’t care much for it when I read it as a teenager. Maybe if I read it now my opinion would be different.