DC Comics has the details...
The following is an excerpt from Batman Day: A Celebration of All Things Dark Knight
Batman is celebrating his 75th anniversary this year, and to mark the occasion, comic shops, bookstores and libraries by the hundreds will be observing “Batman Day,” a full day devoted to all things Dark Knight! On Wednesday, July 23, participating comic shops and bookstores will give away free copies of DETECTIVE COMICS #27 SPECIAL EDITION, an updated take on the comic that first introduced Batman to the world.
The Washington Post has more...
The following is an excerpt from COMIC-CON 2014: DC Comics marks ‘Batman Day’ Wednesday with national celebration–and retail sales
Batman has persevered through so many phases, from a film-noir and sci-fi feel to the high camp of the ’60s TV show starring Adam West, to the Dark Knight of a shadowy, tortured psychology as popularized by Miller’s graphic novels and Nolan’s feature films — right up through the casting of Ben Affleck for next year’s “Batman v. Superman” movie. Batman endures by having as many entry points as he has incarnations.
“Through these 75 years, Batman has been fine-tuned by hundreds of writers and artists into honed perfection,” Meltzer says. “He is perfectly defined, and I maintain, the most perfectly defined literary character. The odd part is, although he’s moved from camp, to dark, to self-hating, to self-confidence, you always somehow know exactly what Batman ‘would do.’ There’s a core that never changes.”