Any reader leafing through the latest issues of comics like Spiderman, The Fantastic Four, The Hulk or Daredevil will be left with the impression that, in the Marvel universe of superheroism, the grip of routine is somewhat stronger than elsewhere and the law of repetition firmly established.

In the June issue of The Hulk, Bruce Banner, the unfortunate scientist, is facing yet another confrontation with Colonel Ross, his all-time adversary and father of Banner's happily unhappy love, Betty. Recent scenes from the life of Peter Parker, aka the Amazing Spiderman, show encounters with old allies and new enemies, take-out dinners and reflections on the nature of heroism. All seems quiet on the superhero front - or, if not exactly quiet, then at least business as usual. Nothing indicates that, not so long ago, the routines of Marvel's protagonists were seriously disturbed.

The disturbance came on September 11 2001, when the city that had served as a setting for countless superhero comics was attacked by two planes, and no knight in a bodysuit or on a shining surfboard intervened to prevent the catastrophe that followed. Only retrospectively, intervention became possible, and it was not long before Marvel published two comic books in reaction to the attack.

Both were planned and presented as benefit products, and, together with Marvel's 9/11-themed Spiderman Comic, they turned in at least $1m in net profits, which makes them by far the most succesful fundraising project in the comics industry. No competing publication (such as the DC/Dark Horse/Chaos!/Image cooperation on 9-11, a two-volume edition) received as much attention, and none is quite as fascinating and problematic as Marvel's attempt to establish an act-first-talk-later notion of heroism.

The first Marvel book, Heroes, was published in December 2001. This was particularly interesting in its effort to unite icons old and new - or rather, in its ambition to establish new icons while simultaneously reintroducing old ones. Many of Marvel's famous characters, such as Spiderman, the Silver Surfer and Captain America, were resurrected and represented alongside the protagonists of 9/11 - a tribute to the firemen, police officers and other rescue workers that must be regarded as an extremely successful PR coup.

The second book, published in February 2002 and titled A Moment of Silence, is interesting for its decision to focus on images, not on words, in order to honour these new heroes. Wordlessness here becomes a policy that is not restricted to the question of how to respond to the heroic deeds (and deaths) of "that day", but aims at discrediting discourse and discussion about 9/11 in general.

The front page of Heroes is subtitled: "The world's greatest superhero creators honour the world's greatest heroes." Thus, the first equation is not between superheroes old and new, but between the heroic fighters of Ground Zero and the superheroes of the comics industry, creating those characters that made Marvel the leading publisher in the field. As a matter of fact, Heroes brought together a very diverse group of comic artists, some of whom - like Frank Miller and Alan Moore - were known for their "rebellious" or ironic approach to the genre.

After 9/11, however, all seemed ready to put that behind them for a cause that neutralised any tendency to treat the subject other than with the utmost earnestness. Equally important, many contributors had hitherto been associated with other publishers. The unifying force of the "good cause" seemed considerable, transgressing professional boundaries. Interestingly, though, what was true for the artists applied only partly to their characters. The two leading DC superheroes, Superman and Batman, are absent from the panels of the Marvel comic book, the laws of copyright being too rigid to permit any cross-promotions where DC's most important trademarks were concerned.

Among the Marvel characters who make an appearance in Heroes, there are two who figure more prominently than the rest, both for a good reason. Captain America had been invented as Marvel's superweapon against Nazi Germany in 1941, leading the way a whole year before the US finally went to war. The Hulk, meanwhile, would unfold his devastating superhuman powers only if he was "made angry". Together, these two seemed a good choice for driving home the notion of yet another historic cause, stressing the connection between anger and justified violence without having to depict anything more than a well-known and well-respected protagonist.

Interaction between the old and the new heroes took various forms. Sometimes, it is salutary. In other panels, it celebrates the glory of joint forces. Other images reverse the hierarchy between the human and the superhuman by showing, for example, a nearly broken Captain America receiving orders and a friendly pat on the back from a policeman and a fireman, thus becoming a subordinate cooperator in the struggle against the horrors of Ground Zero.

The larger part of the panels, however, is reserved for the NYFD and NYPD personnel alone, always in uniform, sometimes desperate yet never tiring and just as impressive in their poses as the characters summoned from Marvel's past. It is hard to decide if Heroes seeks to establish the heroes of 9/11 as equal or as superior to the older, more familiar ones, but, all in all, the concept is genealogical, representing NYC officials as the next generation in charge of the city's safety.

A different discourse on heroism and its contemporary forms can be found in Marvel's second 9/11-themed publication, A Moment of Silence. The paradigm here is not continuity but discontinuity, expressed in the explicit opposition of "fictive" versus "real" and the implicit opposition of adolescence versus adulthood. Rudolph Giuliani, who consented to write an introduction to A Moment of Silence, hinted at both when he declared: "I think we all now realise that we do not have to read fiction to find examples of heroism. The real heroes in American life have been with us all along. Our firefighters, police officers and other rescue workers put their lives on the line every day to protect the rest of us from danger."

Shifting the focus from fictive characters to NYC officials is thus understood as a transition from the heroes of everyone's childhood to those of everyday life, from the realm of fantasy to that of the "real world", and from the age of naivety to that of responsibility. No more Spiderman and Hulk for we who have encountered the first challenge of a new millennium; the stories collected in the book will deal with ordinary people showing extraordinary bravery, setting an example for a nation that braces itself for the conflicts to come.

The telling of the stories happens in a way that is remarkable for a medium usually known for bringing together image and text. A Moment of Silence is presented as an example of wordless commemoration, a tribute to those who did not waste any time on words but immediately proceeded to action. In the epilogue, the principle of proceeding to action without delay is appropriated by Marvel president Bill James himself, who underlines that the editors did not hesitate to assemble the pick of their artists to publish first one, then a second book in honour of New York's self-sacrificing heroes: "This just felt like the right thing to do, so we did it."

What they did was basically two things. The first: to banish words from nearly all panels in the book's four stories, relegating them to the margins - that is, to the introduction, the titles and the closing lines that frame each of the narratives. The second: to underline the superiority of deeds over words, action over speech, by clearly associating discourse with a state of helplessness and presenting speech as dangerous hindrance or escapist form of reaction.

The first story focuses on an exchange of looks and keys that makes an old building inspector part of an NYFD squad. The second locates the silent moment at the end of the story when a fireman's wife finally leaves her post in front of the blaring television and takes her two sons downtown to confront the reality of their loved one's death in action. The third employs speech only to cut all speech short, when a rescue worker utters the order "Quiet!" while listening for signs of life. The last stages the marvellous return of a husband and father as the moment of deliverance from words that had hitherto dominated the family's interactions in the form of petty quarrels. All in all, the policy of wordlessness marks speech (aka debate, discussion, questioning) as a totally inadequate response to the attack. As such, it might have had its share in promoting the idea that the events of 9/11 were not an occasion for discourse.

· Michael Nyman says:

"Stefanie Diekmann is a German cultural commentator. In a sense, her subject is incidental; what is important is that her writing comes from a cultural and philosophical standpoint that isn't well represented in Britain. I really like her take on cultural artifacts, which in this instance has led her to a new way of looking at September 11 2001."