The hallowed issue of Action Comics number 1, which marked the debut of Superman in 1938, sealed in a collecting slab and grade 8.0. It sold in a private sale conducted by Metropolis Collectibles for $1m.

Enjoy unlimited access: just £1 for 12 weeks

Subscribe now

Action Comics number 1, featuring the first appearance of Superman, is the Holy Grail of all comic book collectors. Seventy-two years ago it cost ten cents: last month a collector parted with $1m in a private deal for the privilege of owning one of the best to survive.

Comics are all about condition, but even seasoned collectors of comics from the so-called Golden Age (1938-1955) are prepared to accept any number of flaws to own one of perhaps 100 surviving copies of this issue. However, the $1m comic looked as if it were printed yesterday.

Stephen Fishler, the co-owner of New York dealership Metropolis Collectibles, who brokered the private sale, was the creator of the ten-point grading scale that is now used universally to evaluate the condition of comic books. He gave it an 8.0, making it the second-highest graded copy known to exist, and set its price way above the previous record-holder, another Action Comics number 1 with a grading of 6.0, sold in 2009 for $317,200.

It gives some idea of the escalating value of the best Golden Age comics that Fishler disclosed he had first sold the $1m comic in 1995 for $150,000.

The buyer, described as a well-known New Yorker with a pedigree collection, already owned an Action Comics No. 1 but wanted a higher-grade copy. Vincent Zurzolo, co-owner of the dealership, described the sale as "the single most important event in comic book history".

But Superman had a rival.

As news of the $1m private deal broke on February 23, an online auction of comic books conducted by Heritage Auctions of Dallas was approaching its endgame. And already, with 48 hours of bidding remaining, a copy of Detective Comics number 27 had reached $425,000.

If Action Comics number 1 is the most desirable of all Golden Age comics then a close second is Detective Comics number 27, featuring the first ever appearance of Batman. It was innovative as a single-theme comic in the days when a variety of features was the norm.

Alongside a May 1939 cover date is the striking cover by artist Bob Kane who, with writer Bill Finger, is generally credited as a co-creator of the character. 'The Batman' - who, like Superman has been in continuous publication ever since - appeared in a six-page story that also introduced the characters of Commissioner Gordon and Bruce Wayne.

The second-to-last panel reveals that the mysterious caped figure and playboy Wayne are one and the same.

Heritage called this copy "perhaps the most desirable comic book we have auctioned to date," finding only inconsequential faults and little signs of discolouration. It, too, was awarded 8 out of 10 and could claim to be the highest-graded unrestored copy to have appeared on the market.

By the time the sale closed on February 25, bidding had reached $900,000 - with the buyer's premium, that took the price to $1.0755m, just above the private deal price for the Superman comic.

We await the next instalment…