This issue is a variant of The Walking Dead (Image, 2003 series) #100 [Cover A].
There exist further variants.
This retailer incentive variant was limited to 500 copies signed by Robert Kirkman.
This page contains the indicia and credits for this issue with a recap of the story so far.
Letters from David Fiorito, Jack Russell, Matt Ferguson, Vernon Smith, Kenneth Taber, Will Tucker, Andrew Barr, and Dave Sunhammer.