"Worlds live! Worlds die!"
By 1985, the continuity of DC was a convoluted mess. Multiple and alternative earths were established to explain continuity lapses, but even then, editorial feared that the whole multiverse concept was already too complicated. Therefore, they decreed that a major revision of some sort had to be made. This monumental task of house-cleaning was handed over to then-hot New Teen Titans creative team of Marv Wolfman and George Perez. Thus, the complex saga spanning over 12 issues was born.
The whole narrative hinges on intrinsic duality of nature: for every action there is an equal and opposite reaction. The Monitor has his own antithesis
Muddy mess all tidied up, ey?
The resulting cannon-fodder notwithstanding (including major characters from Earth-1 such as Supergirl, the Flash, and Wonder Woman), the aftermath of the Crisis provided a fresh start for DC. They cashed on heavily on the opportunity to launch new titles and to update various storylines.
In some aspects, they were very successful. Case in point was with the character of Wonder Woman. She didn't die after all, but was de-evolved into clay, and the time table re-set on her along with the Amazons. George Perez headed the creative team that launched her into the new (and single) DC-verse, strengthened the ties of her Greek mythological origins, and provided a very plausible insight into her ironic characterization as the warrior-princess seeking peace in a man's world.
On the other hand, while John Byrne's re-imagining of the Man of Steel was initially received with unanimous praise, it spawned massive continuity glitches in its wake. This time, there are no Kryptonian survivors from the barren and sterile planet save for a lone baby space-warped to Earth in a birthing matrix. He grows up with the Kents somewhere in Middle America as a normal kid and teenager. No superheroic capers for Clark Kent, and he only dons the Superman costume in his adulthood.
That would've worked out fine, except for one, not so-slight problem: the Legion of Superheroes. A huge fan-favorite title enjoying brisk sales, the whole concept hinged on the idea of teenagers, 1,000 years in the future, forming a band of heroes with the exploits of Superboy as their inspiration. But wait, Byrne said that there was no Boy of Steel anymore, right? The resultant explanation of Byrne involving pocket Earths and dimension hopping proved too much of a headache to handle for both the editorial staff and the readers. Sales quickly plummeted, and several years later the title had to completely re-booted from scratch to provide new origins for the group.
But taking the opus as it is, Crisis on Infinite Earths stands the test of time in its majestic breadth of story-telling. True, Wolfman's dialogue may sound awkward and clunky at times, but that can be attributed to the writing style of the period. The George Perez look may also be anachronistic from the modern point of view, but for my money's worth, no artist approaches him in terms of detailing something even as minute as the background. And with literally cast of thousands, he makes a breath-taking and magnificent job in each panel and spread of the comic book. His artwork is even more spruced up by the inks of the veterans Dick Giordano, Jerry Ordway, and Mike DeCarlo, formidable artists on their own right.