KHALID KHANNOUCHI is back in town, winner of the greatest marathon in history. Who says it was the greatest marathon? In a book just published, William Cockerill, a keen club runner and captain of Belgrave Harriers, rates the 2002 London Marathon men’s race, in which Khannouchi set a world record after shaking off Haile Gebrselassie and Paul Tergat, as the best so far.

Yet, as weighty and thoroughly researched as the book is, The 50 Greatest Marathon Races Of All Time could be out of date by Sunday. Khannouchi, twice the world record-holder, the first time as a Moroccan, the second as an American, is listed as only the joint-fifth favourite in a London 2006 field that looks as strong as any army yet sent into marathon battle.

“It’s going to be an explosion on Sunday,” Tergat, the world record-holder from Kenya, said, even after his own participation was ended this week by injury. Gebrselassie, from Ethiopia, the most accomplished of track runners now giving the marathon his undivided attention, lines up for the first time since 2002 and faces a field of formidable quality.

It includes Stefano Baldini, from Italy, the Olympic champion, Jaouad Gharib, from Morocco, winner of the past two world titles, Evans Rutto and Martin Lel, the 2004 and 2005 London champions, and Hendrick Ramaala, from South Africa, the 2004 New York City Marathon champion who lost his title in a desperate dip finish, in which he fell, with Tergat last November.

It says much about the status of Paula Radcliffe in Britain that Khannouchi’s 2002 victory, and the contributions of Gebrselassie and Tergat towards an absorbing race, were relegated to the subtext. On the same day, on the same course, Radcliffe had made the fastest marathon debut by a woman. Britain’s gallant track loser had found her event.

Four years on, Radcliffe’s debut race cannot be found in the top 50 greatest marathons, according to a book that takes the 1896 Olympic Games in Athens as its starting line. You cannot have a race without a set of rules and Cockerill has written his own. Perhaps unwisely, he has set a condition that a race winner may appear in that capacity only once.

This means that, never mind London 2002, Radcliffe’s world mark on the same course a year later — still three minutes faster than any other woman — does not feature. That is because her win in New York, after a close race with Susan Chepkemei, from Kenya, 11 weeks after the Briton pulled out of the Athens Olympics with four miles to run, has been chosen as her permitted one top-50 entry.

Wisely, the author has introduced a safety net to catch any criticism. “All the best races from all the top marathoners from the last 100 years plus have been examined and I have selected what I perceive to be their greatest race, battle or victory,” we are told. “It means that the list has terrific variety with 50 different protagonists and avoids any essays being too repetitive. For instance, Steve Jones’s spectacular back-to-back wins at Chicago in 1984-85 deserve inclusion but their tales are similar.”

Cockerill, though, has, as he put it, “piggy-backed” other great marathons won by an already listed athlete on to their main event report. For the top women’s race, and No 7 overall, Uta Pippig’s victory in Boston in 1996 is selected. If it seems at first glance — six minutes outside the world record of the day — to have little claim, the race scores on the numerous criteria used to establish the rankings. These include quality of field and time, profiles and drama of the event and newsworthiness.

The manner of Pippig’s victory — early stomach cramps and diarrhoea, trailing Tegla Loroupe, from Kenya, by 200 yards with three miles to go — was dramatic and complemented the German’s three wins in Berlin and one in New York. Cockerill has dug into the Pippig life story, her early escape from East Germany to West and her long battle to prove her innocence over a drugs ban.

In this case, and others, the ranking alone is deceptive. The No 47 entry, for example, is listed as the 1954 Commonwealth marathon won by Joseph McGhee, from Scotland. Enticingly subtitled “history’s grisliest marathon”, it turns out to be the fascinating story behind the multiple collapses of Jim Peters inside the stadium, having entered 18 minutes ahead of McGhee.

The book covers not only the great marathons but the personalities and circumstances around them. From No 50, the 1967 Boston Marathon in which Kathrine Switzer became the first woman to run a significant marathon with an official number, having obtained it by sharp practice, through No 24, the sad case of Rose Ruiz, an impostor who refused to return her 1980 Boston “winner’s” medal, to No 1, the riveting personal story of Khannouchi, the tales keep coming.

At more than 500 pages, the book delves into athletes’ post-careers, such as that of Abebe Bikila, the double Olympic champion, from Ethiopia, who was disabled in a car accident but competed in a wheelchair in archery at the 1970 Paraplegic Games.

As Cockerill submits, earlier marathon works have been either detailed accounts of a particular event or broad overviews lacking depth. Finally, the marathon has a book worthy of its long and epic journey.