Some of my favorite light reading are the thrillers of Barry Eisler. As he's gone along, the overlaps in his characters/series have become more complicated. So, in a fit of OCD and with a nod to the Terry Pratchett Reading Order guide, I made this chart. I offer it here for the edification of all and sundry. But do take the compiler's note about how you can start anywhere seriously.
(Click for a larger version.)
Incidentally, I got into this because I had just bought my aunt the second Livia Lone book as a present — she'd liked the first — and was trying to think of how to explain who Dox was and how he fits in. It's tricky!
(Now updated for his forthcoming novel The Chaos Kind (October, 2021). Also released under a Creative Commons BY-SA license, in case anyone feels inspired to improve upon it. (Email me for the photoshop file if you want it.)