How long had Batman been at it in DETECTIVE COMICS # 27 (1939)?

[Buried Alien]

DETECTIVE COMICS # 27 (1939) was Batman's first-ever comic book appearance, but the featured story, "The Case of the Chemical Syndicate," was not his first crimefighting adventure. In # 27, Batman was already established as known to both Gotham's criminal world and law enforcement alike, so how long had Batman been at it at that point?

Additionally, when was Batman's first-ever adventure finally told in comic books? Was it not until YEAR ONE in 1987?

Buried Alien (The Fastest Post Alive!)

[bat39]

DETECTIVE COMICS # 27 (1939) was Batman's first-ever comic book appearance, but the featured story, "The Case of the Chemical Syndicate," was not his first crimefighting adventure. In # 27, Batman was already established as known to both Gotham's criminal world and law enforcement alike, so how long had Batman been at it at that point?

Additionally, when was Batman's first-ever adventure finally told in comic books? Was it not until YEAR ONE in 1987?

Buried Alien (The Fastest Post Alive!)

'Tec # 27 itself doesn't give any answers, though we can surmise that its pretty early in Batman (or should I say Bat-Man's) career, since it seems that Gordon has only vaguely heard of him before.

Then, twenty years later, 'Tec # 265 gives us "Batman's First Case", which, as it says on the tin, reveals Batman's first-ever adventure (in pre-Crisis continuity anyway), where he takes down a criminal named 'Slugsy' Kyle. The story is written by Bill Finger, so I suppose that gives it a certain added 'canonical' status.

Finally, Secret Origins # 6, published in 1986, gives us a definitive answer to these questions with the retelling of the Golden Age Batman's origin. This story confirms that the 'Slugsy' Kyle case was Batman's first adventure, and then frames "The Case of the Chemical Syndicate" as his second adventure.

So, to sum up, there's a story published nearly 50 years after 'Tec # 27 that confirms that "The Case of the Chemical Syndicate" was Batman's second ever case...though you can argue that its a retcon and was never Bill Finger or Bob Kane's original intention.

One interesting point is how both the pre-Crisis and post-Crisis depictions of Batman's first adventure show him as being less then fully effective. He pretty much gets sucker punched by 'Slugsy' Kyle in the former, and in the latter, he's stabbed in the foot by one of the burglars he takes on and just about manages to stop another one from falling to his death.

[Restingvoice]

Gordon is still chasing after him as a vigilante, plus Robin, a year later, after Joker showed up. So you can say that the whole thing up until that point is Year One.