Twelve years after her last full-length graphic narrative appeared, Posy Simmonds’s latest examination of dark deeds among the English middle classes, Cassandra Darke, leaves me pondering the language of pictures and that slippery and highly contentious concept ‘visual literacy’. Simmonds’s tale of the mean-spirited art dealer Cassandra Darke is told largely through the author’s brilliantly executed and structured artwork, accompanied only by dialogue. This reversal of the usual roles of word and image calls into question the meaning of the term ‘reading’. The author’s exquisite draughtsmanship is augmented by warm and cool greys, punctuated by the salmon-pink glow of light from shop windows and the occasional blast of vibrant cadmium yellow. When it comes to books, design is often regarded merely as a process of embellishment – ‘making things look nicer’. But here it is a key aspect of the book’s content.

Led by the children’s book market, which has played a significant role in the recent print revival (but not before a good deal of money was lost in the development of so-called ‘story apps’), the world of publishing is now awash with big, beautiful, tactile hardback books demanding to be held and touched, a collective riot of embossing, debossing and spot-lamination. We appear to be in a new golden age of design and illustration for print in children’s and adult literature. Yet in this country we have never been the quickest to appreciate the art of visual storytelling, despite our long and distinguished history in the field. And when it comes to graphic literature, we are only just beginning to catch up with the French and Japanese in appreciating the genre as something more than a childish form for the adolescent. In many cultures, of course, the picture book is not seen as something to be consumed exclusively by very young children.

Perhaps the root of the problem lies in the muddle we get into around language and terminology. Visual text, sequential art, narrative art, call it what you will, is a very different beast when compared with traditional illustration, wherein the image is subordinated to the written word, serving to augment and embellish rather than functioning as an integral, equal partner in meaning-making. Scott McCloud, in his brilliant comic-format tome Understanding Comics, tackles the thorny terminology issue with a hint of irony as he speaks to us from within the frames of his own drawings, trying to explain what a comic is or isn’t through fractious dialogue with various other interested parties, ending with the usual cumbersome concoction when trying to decode the language of pictures into words: ‘juxtaposed pictorial and other images in deliberate sequence, intended to convey information and/or to produce an aesthetic response in the viewer’.

Practitioners, perhaps following the noble tradition of illustrators ‘knowing their place’ and fearing accusations of pretentiousness, seem to universally dislike the terms ‘graphic novel’ and ‘graphic novelist’, paradoxically preferring ‘comics’ and ‘comics writer’ just to confuse us further. But sales of graphic literature have risen dramatically over the past decade and their creators (most recently Nick Drnaso, whose Sabrina was longlisted for last year’s Booker Prize) continue to find their way onto literary awards lists, sometimes to the discomfort of judges and reviewers. ‘Comics’ are traditionally seen as easy to read and disposable in nature. It is certainly the case historically that visual storytelling has often been closely connected with illiteracy, from early cave paintings through records of epic battles on Trajan’s Column and the Bayeux Tapestry. The broadsheets and chapbooks of the 17th and 18th centuries, with their crude woodcut images, were hawked around to a largely illiterate public, though some featured early examples of word balloons.

But when it comes to book-length comics for adults, many highly intelligent grown-ups still confess to simply not knowing how to read them or talk about them. All this eighteen years after Chris Ware won the Guardian First Book Award for his relentlessly bleak but funny Jimmy Corrigan: The Smartest Kid on Earth. Within the comics community, the attempts of cultural commentators of the day to review it on Newsnight Review have become legendary. Mark Lawson, Tom Paulin, Miranda Sawyer and Craig Brown bumbled their way through an excruciating conversation, having been forcibly relocated some distance outside their comfort zone: ‘Do you judge it on the pictures or the words?’ ‘Actually I think the form works better with Tintin … where it’s light and funny and breezy.’ ‘Well, I mean I haven’t read it, but…’ ‘So ugly…’

Some of the most successful attempts to examine this worrisome hybrid have, like McCloud’s Understanding Comics, themselves been delivered as sequential visual texts. Nick Sousanis’s Unflattening was submitted in comic form as a doctoral thesis at Columbia University before being published by Harvard University Press. It examines how Western culture has embedded in all of us an assumption of the primacy of word over image and looks at the ways we construct knowledge. Borrowing from Edwin A Abbott’s 1884 novella Flatland, which portrays a world populated by two-dimensional beings who struggle to process the idea of ‘upwards’, he explores and communicates arguments in a way that would not have been possible through verbal language alone.

Perhaps it is simply the fact that the traditional text and the comic share the same physical packaging that confuses us, presented as they are in bound sections of folded paper between boards in an object known as a book. Some would argue that the comic format is closer to the medium of film. As McCloud suggests, a sequence of animation stills is really just a very slow-paced comic.

However we want to label Cassandra Darke, it is good. And all those printed images sure do make it smell nice.