In June 1939, Detective Comics #29 is the first story to feature The Batman‘s use of gadgets. This much longer story (10 pages) featured Batman’s first “arch criminal”, Doctor Death and lots of action: Batman swinging around the city on his rope, Batman scaling a building, Batman getting shot, and finally vanquishing his foe.
I like how we have had three Batman stories so far and no real revelations about Bruce Wayne’s social life, his motivations, etc.