Batman historian Les Daniels credits Gardner Fox, (the first writer other than Bill Finger to write the adventures of Batman in Detective Comics), with introducing the utility belt concept in Detective Comics #29 (July 1939). In its first appearance, Batman's utility belt "contain[ed] choking gas capsules." Two issues after the utility belt debuted, Fox also wrote the first appearance of a bat-themed weapon, when the batarang debuted in the story "Batman vs. the Vampire" in Detective Comics #31 (Sep 1939).