Issue Detective 625
Subtitle Abattoir!
Date January 1991
Writer(s) Marv Wolfman
Artist(s) Jim Aparo, Mike DeCarlo
storyline Abattoir was broken out of Arkham. He attacked a political rally, then went after Vicki Vale when he caught her taking pictures of him. Batman saved the photographer and uncovered that the politician had sprung Abattoir; they were blood related.

Issue Detective 626
Subtitle Return to the Electrocutioner
Date February 1991
Writer(s) Marv Wolfman
Artist(s) Jim Aparo, Mike DeCarlo
storyline A new Electrocutioner was in town. Batman went after him while GCPD was in turmoil without Gordon (who was in the hospital after his recent heart attack). He figured out the Electrocutioner was going after gangsters who'd ripped off gangsters and stopped him. 

Issue Detective 627
Subtitle The Case of the Chemical Syndicate (4 takes on the first ever Batman story: the original, the thirtieth anniversary edition, and two new versions)
Date March 1991
Writer(s) version 1: Rob't Kane version 2: Mike Friedrich version 3: Marv Wolfman version 4: Alan Grant
Artist(s) version 1: Rob't Kane version 2: Bob Brown, Joe Giella version 3: Jim Aparo, Mike DeCarlo version 4: Norm Breyfogle, Steve Mitchell
storyline version 1: Batman stopped a killer who was attempting to take over a chemical company by killing off his partners / co-owners.
version 2: Batman and Robin tracked down a killer who took down two chemists working on war technologies. It turned out to be a member of the team trying to get sole ownership of their discovery. 
version 3: Batman showed up on the scene after a chemical plant big-shot was killed. The man was melted into his taxi by someone spraying toxic waste. A second was killed along with his wife and some innocents by this new villain, Pesticyde. Batman found out the third of the four owners was crippled from an accident at the plant. He stopped the man's daughter before she could kill her father's last living partner. 
version 4:
Batman and Gordon investigated when a top chemist was found dead. Batman witnessed a second one die and caught the killers. They'd been hired by the partner of the two dead men. Gordon found the third hanged with a note. Batman knew it was no suicide - the real killer attacked and fell into a vat of chemicals and died.

Issue Detective 628
Subtitle Hearts
Date April 1991
Writer(s) Marv Wolfman
Artist(s) Jim Aparo, Mike DeCarlo
storyline Abattoir broke into an aviary, killed the keeper and all the doves, and cut out their hearts. He then attacked a dairy farm, doing the same to the cows. Batman researched any similarities and stopped a train wreck the madman had planned. He captured Aboittor. 

Issue Detective 629
Subtitle The Hungry Grass
Date May 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Steve Leialoha
storyline Strange, unseen forces produced reenactments of past crimes in Gotham City. A man wrongly imprisoned was spreading cursed grass throughout the city. The grass brought forth any injustice that had happened upon where people tread on it. Batman tracked the man spreading it and destroyed the remaining grass.

Issue Detective 630
Subtitle And the Executioner Wore Stiletto Heels
Date June 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Mike DeCarlo
storyline Batman tracked an escaped hitman who was scheduled to be executed and returned the man to police custody.

Issue Detective 631
Subtitle The Golem of Gotham part one
Date early July 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Mike DeCarlo
storyline Batman patrolled a neighborhood that had been recently plagued with hate crimes. One of the residents, remembering 1937 Germany, tried to create a demon to save him. He succeeded and the beast of clay began attacking the attackers. Batman came face-to-face with the beast. 

Issue Detective 632
Subtitle The Golem of Gotham part two
Date late July 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Mike DeCarlo
storyline Batman realized what it was and went after its creator. After a battle with the beast, Batman convinced the man to down the golem. 

Issue Detective 633
Subtitle Identity Crisis
Date early August 1991
Writer(s) Peter Milligan
Artist(s) Tom Mandrake
storyline Bruce Wayne washed ashore with no idea how he'd gotten there. He went home to find there was no batcave. Alfred and Tim had no idea what he was talking about when he mentioned it or being Batman. He bought some hiking gear and went out in search of the fake Batman that had been impersonating him. Batman defeated him and showed him that he wasn't Bruce Wayne, but the Synaptic Kid - a psychic who'd tried to get into Batman's mind. He snapped trying to do so.

Issue Detective 634
Subtitle The Third Man
Date late August 1991
Writer(s) Kelley Puckett
Artist(s) Luke McDonnell
storyline Batman investigated the killings of two Swiss ambassadors who'd been killed by what appeared to be axe cuts to the chest. Upon further checking, they were hit with bare hands. He checked on the whereabouts of the other three people who could perform that maneuver and confronted the killer. The heartbroken assassin gave up without a fight.

Issue Detective 635
Subtitle Mind Games
Date early September 1991
Writer(s) Louise Simonson
Artist(s) Jim Fern, Steve Mitchell
storyline Professor Powder escaped Arkham and begged for the help of (and warned) Batman and Gordon. They experienced strange digitized hallucinations as they saw Powder killed by a car. Parts of Gotham City were transformed into a video game for short periods of time.

Issue Detective 636
Subtitle Mind Control
Date late September 1991
Writer(s) Louise Simonson
Artist(s) Jim Fern, Steve Mitchell
storyline Another video game attacked occurred in the Batcave. Batman and Robin survived due to Robin's knowledge of the specific game. They dug up a file on one of Arkham's newest inmates - a young boy who was a champion video game player who could reconstruct video games. They went after him; he was being tortured and controlled by a doctor who he'd defeated in one of the contests.

Issue Detective 637
Subtitle Control Freak
Date October 1991
Writer(s) Louise Simonson
Artist(s) Jim Fern, Steve Mitchell
storyline Batman and Robin used the games elements to destroy the doctor's equipment, ending the broadcast mass hallucinations. 

Issue Detective 638
Subtitle The Bomb
Date November 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Mike DeCarlo
storyline A military deserter stole a top secret device - a human who could create explosions, possibly catastrophic. The first incident occurred in a bus station - 30 were killed. Batman found the bomb and got her out of the suit she was confined to. She was not a sadistic killer like the army told Batman (they'd actually set off the explosion at the bus station to show Batman how dangerous she was). She told Batman about herself, and how the military had kept her hostage and drugged up. Batman kept her hidden from them not knowing she'd die without her medication.

Issue Detective 639
Subtitle The Idiot part two: The Queen of Hearts
Date December 1991
Writer(s) Peter Milligan
Artist(s) Jim Aparo, Mike DeCarlo
storyline (continued from Batman 472) 
Batman only ingested a bit of the drug when some of the stock went airborne. He worked through the effects and gave chase to the manufacturers / dealers. He caught one and forced him to take him to the source of the drug. They were attacked by children under control of the drug.
 
(continued in Batman 473)