Batman #1 - First appearance of the Joker (with Joker Venom) and Catwoman and the first Batplane
Batman #2 - The Joker and the Catwoman first meet
Batman #3 - The first time the Catwoman wears a costume
Batman #5 - Bruce Wayne gets a new girlfriend, Linda Page. Queenie, the Joker's henchwoman, deduces that Batman is Bruce Wayne. She dies when she saves Batman from the Joker's bullets. Queenie would appear years later in an episode of the TV series.
Batman #7 - Commissioner Gordon names Batman an honorary member of the Gotham City Police Department
Batman #12 - First appearance of Batman's underground laboratory,
hanger, and the Hall of Trophies
Batman #14 - The last time the Penguin commits murder until the 1970s
Batman #16 - First appearance of Alfred
Batman #24 - Professor Carter Nichols sends Batman and Robin on their first trip through time, back to ancient Rome
Batman #25 - The Joker and the Penguin first meet
Batman #47 - Batman's origin is retold and Batman meets Joey Chill, the man who killed his parents
Batman #48 - "1000 Secrets of the Batcave"
Batman #49 - First appearance of the Mad Hatter and Batman meets reporter Vicki Vale
Batman #61 - The Batplane is replaced by the high-tech Batplane II
Batman #62 - The Catwoman claims she turned to crime while suffering from amnesia, and reforms
Batman #105 - Batwoman appears for the first time
Batman #121 - Introduction of Mr. Zero, later called Mr. Freeze
Batman #139 - Betty Kane (neice of Batwoman) becomes the first Batgirl
Batman #164 - Elevator leading to the Batcave is added
Batman #181 - First appearance of Poison Ivy
Batman #197 - The Catwoman now wears a costume similar to the one in the TV series, but colored green. She and Batgirl first meet
Batman # 208 - First appearance of Mrs. Chilton (in Silver-Age telling of Batman's origin), she was Philip Wayne's housekeeper who helped him raise Bruce. Unknown to Bruce, she was the mother of Joe Chill.
Batman # 216 - Alfred's last name Pennyworth is introduced. Introduction of his brother Wilfred and niece Daphne.
Batman # 217 - Dick Grayson leaves Wayne Manor for college, Bruce closes down the Manor and he and Alfred move to the penthouse above the Wayne Foundation building. Bruce is determined to return Batman to his early creature of the night persona (complete with him again being referred to as "The Batman".)
Batman #232 - First appearance of Ra's Al Ghul
Batman #251 - The Joker returns, once more a ruthless killer in "The Joker's Five-Way Revenge"
Batman #253 - Batman meets pulp adventurer The Shadow
Batman #258 - Arkham Asylum appears for the first time in a Two-Face story, "Threat of the Two-Headed Coin!" by Denny O'Neil and Irv Novick. The Arkham name obviously is an intentional homage to the works of H.P. Lovecraft. Lovecraft's Arkham was a fictional city in Massachusetts, a ficitionalized version of Salem, home of Miskatonic University and the Witch-House. Arkham Asylum as it was depicted in later stories bears no small resemblance to the Witch-House, a cursed boarding house whose architecture was supernatural geometry designed to contact Things Man Was Not Meant To Know! (Grant Morrison riffed on this very heavily in his 1989 ARKHAM ASYLUM graphic novel.)
Batman #348 - Bruce Wayne moves back to Wayne Manor and the original Batcave
