Adam Jay Epstein books in order
2 books in the catalogue, about 13 hours of reading in all; the shortest takes 6 hours and the longest 7 hours.
1 series in the catalogue.
The Familiars
4 books 1 
The Familiars 6.7 h 
Circle of Heroes 6.2 h
The Familiars 6.7 h 2 Secrets of the Crown length not known
3 Circle of Heroes 6.2 h Palace of Dreams length not known