Glad I came across this as I watched a documentary last week about Clarke on Sky Arts. I really knew nothing about him or his work, but am glad I do now and great to see some imagery.
Wasn't he a wonderful artist? His uniqe style is very recognizable. Have you seen his illustrations to Poe's works?
It was interesting that I first came across him through his stained glass work, but I actually think that the illustrative work is much better, perhaps the subject matter helps. I have come across one or two Poe pieces, but would like to see more. I will have to find some time and have a good hunt around online.