I'm interested in these books. The History of DC universe, World of Krypton, and Aquaman the Atlantis Chronicles that's available in DC digital. They're all created in the 80s, I think.
I know they're... probably no longer canon, but it made me curious, for the people who saw it in real time... How long was it before DC decided they're no longer canon?
I only saw the New 52-Rebirth transition in real time. About 5 years. Now some of New 52 is no longer canon, or only partially canon, and you have to fill in the blanks yourself until they actually clarify it.
How long did it take the first time?