It's no secret that Superman is one of the physically strongest characters in superhero fiction, but the feat that most fans believe best shows off his supposed infinite strength wasn't meant to be taken literally. Superman did one incredibly cool feat, and now fans think it proves that Superman has limitless strength - but that's simply not the case.
When it comes to proving Superman's ridiculous strength, there's no shortage of incredible feats to point to. Superman once knocked out the World Forger, and he once fought Doomsday to a standstill. Both of these are remarkable displays of strength. But the event that fans almost always gravitate to is when Superman manages to lift the book of eternity in Final Crisis: Superman Beyond #1 by Grant Morrison and Doug Mahnke.
If Superman could lift an object that has infinite weight - since it has infinite pages - it might seem like he has infinite strength. But that isn't exactly true, as the scene works more as a metaphor than a literal display of strength.
Superman Didn't Actually Lift the Book with Infinite Pages
Final Crisis: Superman Beyond #1 by Grant Morrison, Doug Mahnke, Christian Alamy, Rodney Ramos, Tom Nguyen, Walden Wong, David Baron, and Steve Wands
Many people look at this out-of-context of Shazam and Superman lifting a book of infinite weight. It's easy to assume that this means they have infinite strength, but that's not quite what was happening. This event isn't actually taking place on Earth or even in the main universe at all. Instead, this incredible feat was done in the realm of Limbo. While that might not seem like it makes a major difference, it actually changes everything, because in Limbo, Superman isn't just a man of flesh and blood - he's a myth.

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In the realm of Limbo, Superman represents his own role as a superhero archetype. He is the hero who never gives up and always finds the best possible solution, even if the situation is entirely hopeless and impossible. Superman being able to lift the infinite book is a representation of how Superman's myth will always find a way to succeed, no matter how impossible the odds seem. It's a testament to just how powerful the legend and legacy of Superman is, far more than just the man himself.
Superman Is an Idea That Can Conquer Anything
There's No Threat Superman Can't Face
Superman is one of the oldest and greatest heroes in the world. The main reason for this popularity is that Superman represents hope. He represents the idea that any trial can be overcome, no matter how dangerous or difficult it is. Because of this, when Superman is being represented by his legacy in the Realm of Limbo, he's capable of lifting a book with infinite pages because there is no problem that is too big for Superman to handle. It's a wonderful sentiment that speaks to just how powerful the myth of Superman is, but, unfortunately, it's not an actual physical feat that Superman accomplished.
Superman very much does have a limit to his physical strength, a fact that has been shown many times in DC's comics. Superman lacked the natural strength to fight the World-Forger; he instead needed to be significantly powered up by yellow suns to land a good hit. When Superman fought Doomsday, Doomsday's strength was a perfect match for Superman. Doomsday was one of the first villains that Superman couldn't just outright overpower.
Just like every other being in the world, Superman has his limits, even if they're a lot higher than most people.
Other characters such as Darkseid have managed to physically overpower Superman as well, which clearly demonstrates that Superman's strength is far from infinite. It's certainly a fun idea to have Superman be the man without limits, and that is certainly what his metaphorical legacy is about, but it's not the case for Superman as a character who needs limits on his powers to make his stories work. Just like every other being in the world, Superman has his limits, even if they're a lot higher than most people.
Superman's Actual Greatest Physical Feat Is Just as Impressive
Superman: Man of Tomorrow #12 by Robert Venditti, Scott Hepburn, Ian Herring, and Dave Sharpe
So how has Superman actually proven the wild upper limits of his strength? Though fans have been using this book for years to show that Superman's physical power borders on the infinite, that's not exactly true. But Superman does have a few feats that show that his strength is still close to infinite. Superman has held black holes in the palm of his hand. A Superman variant once punched reality so hard that it shattered, and Superman has knocked out beings who literally create planets. But all of that pales in comparison to Superman's actual greatest physical feat in Superman: Man of Tomorrow #12 by Robert Venditti and Scott Hepburn.
While lifting a book of infinite pages certainly sounds impressive, the actual best display of Superman's strength was when he agreed to switch places with the god Atlas. Atlas desired to be there for his daughter's wedding, and not wanting him to miss it, Superman took on the responsibility of holding up reality itself. Superman then proceeds to hold up reality for twenty-four hours. He held up everything that exists in the DC Universe: every multiverse, every object, every person. Everything that ever existed rested on Superman's shoulders.

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There's no alternate realm trickery for this either. Superman simply held it up with his own strength. This scene isn't a metaphor about Superman or a representation of his importance as a myth; it's just Superman using his raw physical strength to hold up existence. That's significantly more impressive than Superman managing to lift a book of infinite pages, especially since Shazam was helping him.
Superman Has Two Truly Outstanding Feats in His History
Proving the Strength of His Legacy and the Strength of His Body
Superman is a truly incredible character, and while lifting the book of eternity isn't the technical feat of strength that some fans thought it was, it's still no less impressive. Instead of this feat proving Superman's actual physical strength, it proves the strength of Superman's legacy and the importance of him as a mythic hero. This strength is perhaps his most important, as it's the entire reason he still dominates comics despite debuting over eighty years ago.
While his strength isn't infinite, being able to hold up existence is about as close to infinite as anyone can get.
The other feat demonstrates just how strong Superman actually is. While his strength isn't infinite, being able to hold up existence is about as close to infinite as anyone can get. Superman's strength defies all reason. It's pretty absurd that a character could have two different feats that demonstrate different aspects of his power that are on a level that pretty much no other characters achieve. So, the next time someone tries to say that Superman has infinite strength, that's unfortunately not true, but his strength is pretty close to infinite.
Final Crisis: Superman Beyond #1 and Superman: Man of Tomorrow #12 are both available now from DC Comics!