It is said that one of Pablo Picasso's few regrets in life is that he never got around to doing a comic book.

This is the first thing I learn from Paul Gravett's Comic Art (Tate Publishing, £18.99). Picasso liked comics, Rudolph Dirks's Sunday newspaper strip The Katzenjammer Kids in particular, and would discuss them with Gertrude Stein as she sat for a portrait. He understood that comics were an art, even if they weren't his kind of art.

As the title suggests, it is the art of comics that is at the heart of Gravett's book. Sumptuously illustrated, internationalist in outlook and very much up to the minute, it is interested in the space between the panel, the origins of the speech balloon and the comic strip's potential to be radical - he quotes Maus creator Art Spiegelman suggesting that Mad Magazine was "more important than pot and LSD in shaping the generation that protested the Vietnam War" - or reactionary (think of the offensive stereotyping of Africans in Tintin In The Congo).

For all that, Gravett has written the start of a conversation here rather than put down the last word. There is much more to be said about the strengths and weaknesses of the form (the cartoonist Seth summarises it neatly and winningly as a "mixture of poetry and graphic design"; others may disagree), strengths and weaknesses you can find on display in this autumn's batch of graphic novels.

Joe Sacco's The Great War (Jonathan Cape, £20) is easily the most eye-catching - partly down to its unusual format. An attempt to depict the first day of the Battle of the Somme, Sacco has created in eye-straining detail a 24ft-long continuous - and wordless - drawing that concertinas out between hardboards and takes us from morning to night; from General Douglas Haig coming from church prayers to the burial of those who died at the casualty clearing centre. Between the two is a vision of heroism, stupidity, horror and violence in meticulous black and white.

The devil is, inevitably, in the detail: falling bodies, blasted bodies, bits of bodies, a panorama of flesh being systematically and repeatedly reduced to meat. It is a powerful, sustained piece of work, an example of Sacco's journalistic approach. And yet there is a distance between reader and subject. We know none of these soldiers individually.

The horror of the war is clear to see, but maybe not to feel (something Sacco is very capable of doing, as anyone who has read his previous books, Palestine or Safe Area Gorazde, will know).

Gareth Brookes's The Black Project (Myriad Editions, £12.99) makes an interesting comparison in that respect (if admittedly nothing else). This story of a rather twisted adolescent works because it takes us into the mind of Brookes's protagonist, Richard, while never actually showing us his face.

Richard is so desperate to get a girlfriend he starts making one, first with grapefruit, girls' clothes and a picture from a magazine, then with a tape recorder and a decorated plastic skull. Each model is more intricate (and anatomically correct, or as anatomically correct as you can get with cotton wool and fish tank pumps). We are stirring some of adolescent sexuality's murkier currents here, though if anything I reckon Brookes could've pushed the queasiness a little further.

Like The Great War there is an element of excess built into the creation. In Sacco's case it's to be found in the intricacy of the drawing - mostly to do with the fact that this is a graphic novel which is less drawn than sewn. Brookes's story is told via embroidery and lino cut. The result is a bit like Cath Kidston embroidering for David Lynch.

Oscar Zarate's The Park (Self­MadeHero, £15.99) is more conventional than either of these books. Set in a London park, Zarate's first graphic novel for far too long tells a small story (in a soft wash of paint and ink) about four people who are linked by birth and a very minor act of violence - and plus a side order of Laurel and Hardy - to explore ideas of communication breakdown. It's a relaxed story about how fathers influence their children and how those children reflect their upbringing even as they try to break away from it.

And it's a handsome thing. The Argentine cartoonist has a wonderfully expressive line. But there is something a little fuzzy in the telling - as if the emotion it tries to tap into has been softened by cushioned prettiness of the art.

Compare it to Room For Love (SelfMadeHero, £14.99), a starker, fiercer piece of work by the cartoonist Ilya. The story of the unlikely relationship between a middle-class, middle-aged author of romantic fiction and a teenage runaway, it's about sex and love and what we expect from both of these things.

It has its flaws. The narrative all too often lurches rather than glides, and for something that is ultimately about the unknowability of other people, it's not above resorting to predictable back-story revelations. And yet it has an energy and a drive and an appetite that keeps you reading.

Better still is The Encyclopedia Of Early Earth (Jonathan Cape, £16.99), the debut of Isabel Greenberg. Storybook beautiful, it is a work about storytelling set in a mythic past full of gods and kings and shamans, three genius monkeys, a one-eyed giant and two lovers who are kept apart due to magnetic repulsion. Greenberg plunders old stories (the Bible and Homer are just two of the most obvious sources) and refashions them to her own ends. It's a whimsical, light-hearted book that reads like the best kind of bedtime story - a new take on something familiar and much loved.

Greenberg has the advantage of being a new voice, of course; novelty is always attractive. Compare that to someone like Charles Schultz whose Peanuts cartoons are almost invisible because of their overfamiliarity (and affiliated overmarketing). Read either of the latest collections from Canongate, volumes 13 and 14 of The Complete Peanuts (£16.99 each) and it's only the odd reference to contemporary pop culture (a mention of Olivia Newton John, say, ) that dates them. Otherwise it's the same old, same old.

The problem is, as Maus cartoonist Art Spiegelman notes in Co-Mix (Drawn & Quarterly, £26.99), a gather-up of odd comics, illustrations and sketchbooks, that we no longer see how refined and eloquent that "same old, same old" is. "By the early '70s I'd come to associate 'Peanuts' with square Republican girls," he writes at one point. "Rereading it now I'm astonished that a strip so universally popular could be so personal, authentic and … good!"

As Spiegelman says: "Peanuts was 'about nothing' years before Jerry Seinfeld was even born." And what is striking reading these two volumes is how funny these strips are. Funny and heartbreaking. Kids' stuff, you might say. But then which of us has ever really grown up? Schultz knew that all too well. In his work he reduced that to a few lines and a few words that still said so much. He had it down to a fine art, you might say.