Most would naively call them "crackers," although hacking in the 80s for some kids weren't just about phreaking. Back then, some would do anything to get on telenet and tymnet for discovering weird and wacky systems. They're not from academia, so expect "crackers" as their sir name. Even after 20 years, some systems in these networks were so sensitive in nature they will never see print, but you certainly do get a glimpse as to what happened before operation sundevil in the article.
I read his book in high school. Masters of Deception. I really liked it.