The first 10 issues of Detective Comics which feature The Batman (starting with issue no. 27) were the most engaging, exciting, and least dated Golden Age comics I have read thus far. You don't get the Batman origin story until issue #33, but the four issues before that now-legendary issue provide plenty of thrills. I was actually fairly familiar with these stories because my parents gave me Tales of the Dark Knight as a kid and I read it cover to cover several times despite not picking up an actual comic book for another 25 years.
The only drawback in the first 10 issues of Batman is that he meets a lot of generic no-name criminals. He doesn't even meet his first big nemesis until the first issue of Batman, which was the last of the 10 issues I read. In that issue we are introduced to Robin, who just appears as if he had been there the entire time even though he hadn't (It seems like they weren't as married to continuity in the Golden Age. I don't know if they could've even imagined that people would still be reading and dissecting their work 70 years later). Batman #1 is also the first appearance of The Joker, who has a fascination with jewels that doesn't really seem to carry over into further Batman lore. The strength of any superhero lies in his villains, and Batman eventually assembles the greatest cadre of villains anywhere in the world of comic books. By the time I finished the first 10 Batman comics, I could see that Bob Kane was really hitting his stride. He had just developed an all-time great villain in The Joker, and Batman was really turning into the superhero we all know and love. All the pieces were there, and it was only 1940.
The one thing that really struck me in reading these comics was that Batman was an edgy hero even in his early days. He killed several baddies in the first 10 issues, even graphically hanging a couple of them. In the first couple issues, they were a little queasy about tossing bad guys off roofs because they never really showed them flying off. By the last few issues, The Batman is killing guys right and left. This is as dark as Golden Age comics can possibly get, and I love it. I've been a lifelong Batman fan, so the current First 10 standings should come as no surprise:
- Amazing Spider-Man
- Fantastic Four
- The Punisher
- Golden Age Green Lantern
- The Avengers