Green Lantern Vol 2 #43
March, 1966
Cover Artists: Gil Kane, Murphy Anderson

​"Catastrophic Crimes of Major Disaster!"
Writers: Gardner Fox
Pencilers: Gil Kane
Inkers: Sid Greene
Editors: Julius Schwartz

Appearing in "Catastrophic Crimes of Major Disaster!"
Featured Characters: Green Lantern II
Flash II
Supporting Characters: Carol Ferris
Thomas Kalmaku
Iris West
Villains: Major Disaster Next (First appearance)

Synopsis for "Catastrophic Crimes of Major Disaster!"
Hal Jordan and Barry Allen are both shocked when they learn that both Carol Ferris and Iris West have found out their secret identities. Having Flash bring Iris to Coast City so that they can have a double date with Carol and Green Lantern, their date is soon interrupted by an earthquake created by the new criminal Major Disaster. While the Flash saves civilians, Green Lantern goes after Major Disaster, however Disaster manages to escape. Hal realizes that the the secret of their identities might have come out if somebody had read Pieface's secret case book, deducing that although he blanked out Pieface's mind to never remember Flash's secret identity, he never thought to condition the case book to shield his and Flash's secret identities to anybody else.

Checking at Pieface's home, they find that book has indeed been looked at by somebody other than Pieface. Dusting it for finger prints, the two heroes turn it over to the police for analyzing the finger prints. When they return to Hal's dressing room so that Hal can recharge his power ring, the two heroes are shocked to find that their powers have switched. Returning back to the police station, they learn that there are two sets of prints, one belonging to Pieface, and the other to a Paul Booker.

​Using his Green Lantern like powers, Flash tracks down the location of Paul Booker to Major Disasters hideout. While the heroes are on their way, Major Disaster boasts about how he learned of the heroes identities one night when he had broken into Pieface's home to escape the police and came across his Green Lantern case book by stroke of luck. When Major Disaster sends meteors to crash into Coast City, the two heroes go to stop Disaster. Taking the fight to him, and switching their powers back, the heroes make it to Major Disasters lair. Disaster is about to activate one of his devices, but in his hurry to destroy Green Lantern and Flash, he forgets to put on his insulated gloves and electrocutes himself and seemingly dies. Afterwards, they find that the people of Coast City have suddenly forgot all the events of the day, including Carol and Iris who no longer know their secret identities. Hal and Barry surmise that it was probably due to the meteors which Major Disaster attempted to use against them. The two heroes then resume their normal lives, knowing that their identities are safe once more. 

"I've done everything you've ever asked me! I've never shirked a duty! I've suffered and fought--and now you suddenly take away my status as Green Lantern--and give it to Alan Scott? Why? Why? WHY?" - Hal Jordan

Green Lantern Vol 2 #40
October, 1965
Cover Artists: Gil Kane, Murphy Anderson

"Secret Origin of the Guardians!"
Writer: John Broome
Penciler: Gil Kane
Inkers: Sid Greene

Appearing in "Secret Origin of the Guardians!"
Featured Characters: Green Lantern (Hal Jordan)
Green Lantern (Alan Scott)
Supporting Characters: Guardians of the Universe
Doiby Dickles
Villains: Krona Next (First appearance)
Other Characters: Ki-Nilg (First appearance) (Flashback only)
Locations: Earth-One
Coast City
Earth-Two
Gotham City
Oa
Vehicles: Goitrude

Synopsis for "Secret Origin of the Guardians!"
On Earth-Two, Alan Scott is shocked to find that his power ring is not working against a yellow meteor, and yet it is able to save Doiby Dickles' car from a falling tree. Realizing that his power ring seems to have the same properties of the Earth-One Green Lantern, Hal Jordan, Scott travels to Earth-One to tell his alternate reality counterpart of his discovery. However, when Alan tries to show Hal what his power ring can do on Earth-One, he finds that the effect has worn off. Realizing that there might be more going on, Hal suggests they probe Alan's power ring to find out what happened.

The ring begins by explaining that millions of years ago on the planet Oa on Earth-One, a scientist named Krona tried to view the creation of the universe with a device -- something that was forbidden by the Oa society -- however in viewing creation he caused a chain reaction that destroyed his device and created evil in the universe. As punishment, Krona was converted into energy and sent to spend eternity circling the various universes in existence. The Oans then created the Green Lanterns to police the universe and defend it from evil. The ring then explains that the yellow meteor that Alan tried to stop was really Krona, who was able to then transfer his being into Alan's power ring to piggy back into Earth-One.

​Contacting the Guardians, they tell the two Green Lanterns that they are aware of the situation and that Krona is somewhere on Earth. As Krona builds a new device to recreate his original experiment, the two Green Lanterns battle environmental forces that are thrown at them as a result of Krona's experiments.

Not wishing to be interrupted by the two heroes, Krona uses his mental powers to manipulate the Guardians to come to Earth, and demands that Hal turn his title of Green Lantern over to Alan Scott. While Hal is shocked by this revelation, Krona takes control of Alan's body and attacks Hal with it. With Hal defeated, Krona has the Guardians brought to his hideout while the spirit of Alan Scott helps Hal track down it's location. Hal battles Krona and destroys his machine and frees the Guardians. The Guardians then banish Krona once more, and once Alan is restored to his body, the two Green Lanterns part company, Alan returning back to Earth-Two. 

Notes
This issue told the origin of the Guardians of the Universe and established that the DC Universe was comprised of an infinite number of parallel earths, populated by different versions of Earth-One's heroes.
This issue is reprinted in The Green Lantern Archives Vol. 6.