The Compleat Adventures of Jules de Grandin is available only as a boxed set with Volumes 1, 2 and 3.
Cover of Volume 1:
Cover of Volume 2:
Cover of Volume 3:
Seabury Grandin Quinn aka Jerome Burke (1889–1969) was a pulp magazine author most famous for his stories of the occult detective Jules de Grandin, published in Weird Tales with great success.
Seabury Quinn was a contemporary of Robert E. Howard, H. P. Lovecraft and Clark Ashton Smith.
Seabury Quinn. Wikipedia.