Glad you're digging the Joe Ledger experience. I'm having a hell of a lot of fun writing the Joe stories. Working on the third book, KING OF PLAGUES now.
PATIENT ZERO isn't a serial novel. It's the first in a series (followed by THE DRAGON FACTORY, due out March 2 and THE KING OF PLAGUES, due out March 2011). Between each story, however, there are free short stories posted online. And there will be a short story that's a direct sequel in the form of the short story, "Zero Tolerance", which will be published in the print anthology, THE LIVING DEAD 2, edited by John Joseph Adams, scheduled for release in September.
"DEEP, DARK" takes place after PATIENT ZERO and shortly before THE DRAGON FACTORY (which will be released in March 2010).
It's my holiay gift to the many friends of Joe Ledger, Echo Team and the Department of Military Sciences.