“I believe the books are alive”, wrote the great man in his critical biography of 1906. “I believe the leaves still grow on them, as leaves grow on the trees.”

At this point the judicious modern critic says a polite hem-hem and draws a veil, yet Chesterton is a great favourite of George Newlin, editor of the new, astonishing three-volume reference work Everyone in Dickens, and is quoted therein always with approval. Whether Mr Newlin likewise believes that characters continue to sprout in novels he has already meticulously mustered is between the man and his paranoid nightmares. But either way, Newlin forfeited early retirement and spent six dedicated years in New York State typing exhaustive extracts into a computer for Everyone in Dickens. He enumerated more than 13,000 characters from 558 individual works, arranged them chronologically and cross-referenced them in every way he could think of. For his sake, then, we must dearly hope G K got it wrong.

There is a challenge in the title, of course. Everyone in Dickens? is one way of saying it; also Everyone in Dickens? Both are incredulous. Scholars have compiled Dickens encyclopedias and indexes before, but nothing as grand and final in scope as this. Surely there is some tiny character in some tiny fictional fragment that Newlin has failed to include, list, cross-refer and expound upon? Well it would be a sad person who’d look for it. No one before Newlin has ever demonstrated so well that,whatever happens in Dickens - even in the journalism - an identifiable human agent is behind it.

And the glory of it is that every character, down to the merest unnamed spear-carrier, is given enough flesh by the author to go off and live. “Water party-goers, their courage cooled”, runs a satisfying thumbnail sketch of - what? Well, not much more than a thumbnail, probably, if you cared to look it up in Sketches by Boz. “Child, very astonished” runs another; “Office lads, small but in large hats”; “Professional gentlemen, a threesome attempting a glee”.

It is people who make event in Dickens. The instinct to characterise is so powerful in his work that he famously imputes motives and personality to the furniture and the houses. Even in his polemics, he included characters - he simply couldn’t help it. What does the reader remember from the first paragraphs of David Copperfield? The caul David was born with, the chimes and cries at midnight, and the disappointment of Miss Betsey Trotwood? Quite right. But what about the attorney who almost buys David’s caul - who on the very first page of this novel sounds the sour note of meanness that will pervade Davey’s young life? This unnamed man, who offers “two pounds cash and the balance in sherry”, easily earns his place in Everyone in Dickens. He walks on, he walks off. But he leaves things irreversibly changed.

Being an amateur enthusiast, not an academic, Newlin has clearly had fun in the making of this book - fun which doubtless peeves the professionals. For his one-line word-portraits (a list of which always precedes the lengthy extracts he has copied and organised from the texts), Newlin eschews the official descriptions prefacing the novels, and cheerfully invents his own. Thus Bill Sikes in Oliver Twist - officially described as “a brutal thief and housebreaker” - is summed up here as “admired by his dog”. Flora Finching in Little Dorrit should be delineated as “a well-to-do widow, sentimental and affected, but good-hearted”. Newlin, less generous, calls her a “giddy old girlfriend”.

Indeed, as the chronology advances and the pages accumulate into four figures, the editor gets ever more heady and carefree, not to say wild and out of control. By the 1860s and A Tale of Two Cities, Therese Deforge is “a grim knitter” and Sydney Carton “a ne’er do well who does”. And by the time of the last complete novel Our Mutual Friend, Newlin can describe the loathesome Podsnap with what sounds more like a crossword clue than a character sketch: “gave his name to a whole class of pillars”.

It takes a while to learn how to use this book. Reading it is easy, because you start from the front of Volume One and turn pages slowly, chuckling, for about a year and a half. But using it to find a Specific Somebody is the real test - and to be honest, I have not been particularly successful so far. I tried to trace a vivid walk-on character in Our Mutual Friend - the man with two wooden legs who attends Bella Wilfer’s wedding. I assumed he had no name, forgetting Dickens called him Gruff and Glum. And I assumed that if he did appear in the lists, Newlin would quote the glorious line I half-remembered: that he walked across the park at Greenwich rapidly, “as if he were scoring furiously at cribbage”.

Newlin does not quote this line (more peculiarly, he does not quote the Fat Boy in Pickwick Papers saying “I wants to make your flesh creep”, either) - but God bless the man, he can’t do everything. One day, far off, this material will be available on CD-Rom, and it will be the simplest thing to enter “wooden leg” (tap, tap, clunk) and wait for the result. For the time being, however, Newlin includes in Volume Three a handy list of nine wooden-legged characters - but unfortunately I only discovered it after I’d impatiently located Gruff and Glum by other means.

Volume Three (“A Taxonomy”) is the cross-referencing part of the work, and it is phenomenal. I found the wooden-leg brigade under the heading “Named Characters, Miscellaneous Categories (and Certain Fauna)”, where you may also find “cadgers and spongers”, “lodgers”,“litigants” and so on. If any character in Dickens reminds you of someone else, the great Volume Three is where you will find the connection. Here you may learn, to your amazement, that there is only one named cat in Dickens (Lady Jane, belonging to Krook in Bleak House). You will also find lists of hilarious sobriquets for servants such as The Analytical Chemist, The Incapables and The Marchioness.

But when I happily located these lists, I also started arguing. Under the promising heading of “Idler”, for example, Newlin listed only two - Jack Maldon in David Copperfield and Alfred Mantolini in Nicholas Nickelby - and I was astonished. What terrible oversight was this? Dickens is noted for his shiftless, drawling wastrels. Where were Harold Skimpole and Eugene Wrayburn, and Montague Tigg? I started to draft a letter of protest.But then, later, came a separate heading “No visible means of support”, which explained it. Fourteen more idlers were listed here; and still more were to come - under “Wits, lives by”.

How a person is supposed to second-guess such a taxonomy is a mystery. The compensation, however, is that generally the 14 characters you didn’t expect are so interesting that you forget what you were after in the first place. Newlin lists “Equine” instead of “Horses”, too - which is perverse, if there is no cross-reference. Poor Mr Toots in Dombey and Son does not attain a place as an “Admirer”, which is remiss but somehow fitting, because his fate was always to be overlooked. But under “Reader, aloud”, I found a striking omission - striking because I thought T S Eliot had made it famous. Newlin forgets Sloppy in Our Mutual Friend, described by Betty Hidgen as “a beautiful reader of a newspaper. He do the police in different voices”.

However, an editor must have his idiosyncrasies, or he might as well be a machine or a committee - and Newlin is clearly neither. He is, in fact, a hero. If he responds to Dickens in a personal way, that’s his prerogative, since it’s his book. His years at the keyboard have set him thinking about connections and themes, so he gives rein to his own theories. Nobody has been in his position of authority before. So, whereas critics have always noted the prevalence of orphans in Dickens, Newlin makes the subject his own with an invaluable statistical essay - thus handing some lucky research student a PhD on a plate. Biddy, Sydney Carton,Martin Chuzzlewit, Ada Clare, David Copperfield, Charles Darnay, Mr Dick, Edwin Drood, Little Em’ly, Joe Gargery, Walter Gay - the list goes up to 149. The absence of parents is an automatic condition of Dickens’s principal characters; Newlin has proved it as Gradgrindian fact.

A character description one sometimes sees in Dickens is “supernumerary” - which I would think meant someone above the numbers (a godlike figure on a platform with an enormous abacus, like Newlin); but in fact it means in excess of the normal number, an actor who walks on to swell the scene with nothing to say. Only Dickens needs supernumeraries, because Dickens fills every stage to excess. Everyone in Dickens is an exciting, engaging and deeply impressive reference work which renews one’s awe for the immensity of Dickens’s creative imagination. And if Chesterton’s sprouting leaves theory still sounds a bit like nonsense, it may be time to go back to the novels and see what’s grown there since last you looked.

Everyone in Dickens, compiled and edited by George Newlin, Greenwood Publishing, three volumes Pounds 250