*Person picks up a book, smiles and says* "Ooh! That's clever!" I love it when book designers incorporate optical illusion into their designs mainly because they're so clever and as humans, we are drawn to intelligence in the same way we are drawn to beauty and charisma. We want more! The effect of the perceived 'cleverness' of a cover in book design is three-fold. 1. It gets instant attention. Something that grabs the eye to the extent that it gets a person to pick up the book for closer inspection is half the battle when trying to sell it. 2. Cleverness is reflective. When we perceive that something is innately intelligent, it makes us feel clever, which makes us feel good and when we feel good, we are more likely to spend money. And 3. Cleverness gets people talking. Something that is perceived to stand out for making us think - as opposed to some negative reason - creates quite a delicious talking point and, in a busy market place that is increasingly and inexorably dominated by visual social media, the more virtual tongues you have wagging about the cleverness of your book cover the better. Today on the blog, it is my pleasure to share with you a selection of my favourite optical illusion jackets by amazing book designers who employ trompe l'oeil, forced perspective, graphic design trickery and visual innuendo to grab the attention in a very clever way. (NB. If you are easily offended, some of the of the images and themes below are a little bit explicit too so please read on with caution.)

The Vagina: A Literary and Cultural History by Emma L.E. Rees. Cover design by n/a (apparently. I cannot find any record other than that for this title but will keep looking) You really can't get more clever and self explanatory than this book cover. Batter up an old paper back and its nothing special. Position it on end in a v shape with a fleshy rose pink background and the word VAGINA underneath it and you might as well be looking at the real thing. Even to the unintiate, the visual innuendo is as unmistakeable as a physical rendering of the female sex organs complete with a mysterious dark void at the centre to really hammer home the message that this is a serious, no holds barred book about debunking myths and exploring taboos. Totally brilliant (but I probably wouldn't read it on the tube).

The Room by Jonas Karlsson. Cover design by Christopher Brand. Look at all those lines! Name going in one direction, title in another all on a calm, plain gradiented background that only makes sense when we see the man striding purposefully through the centre of the second "O". We're looking at a wall. Or are we?  Because he also appears to have his right leg on a solid floor. The whole image serves to disorientate and confuse and, just when you think you have a foothold on sense you see something else that isn't quite right. It is fascinating and unsettling at the same time. Also, that hole in the "O" looks very small. What is on the other side? What's in the room? Why has he left his bag outside? This cover raises questions to which we instinctively want to seek out the answers. Perhaps they're on the back of the book in the blurb...

Leaving the Sea Stories by Ben Marcus is one of a set of two utterly stunning covers created by Peter Mendelsund. I've shown it here in 3-D along with the spine so you can actually see that it is a 3D graphic design effect and not a real collage of paper waves. In it you can almost feel the movement of the sea as the little words bobbing about and apparently lost are overwhelmed by the choppy blue waves. The 'water' is so powerful in this image and the little isolated words so small and insignificant in comparison and I contend that this is not irrelevant to what is inside the cover.

The Brief History of the Dead by Kevin Brockmeier. Photograph by Patrik Giardino. This photograph of a simple trench coat on a hanger has a serious double-take factor when you realise that there are two hands holding it open to reveal the title. The sense of absence is what chimes with the books title captured beautifully by this very simple graphic design trick.

Pragmatism: A Reader - edited by Louis Menaud. Design by John Gall. I'm not big on philosophy but the dictionary describes Pragmatism as: "an approach that evaluates theories or beliefs in terms of the success of their practical application". While this does not help me to decipher the design process behind this gorgeous image, I love the sense that this book cover presents the idea that if you strip away what is above then you will find beautifully framed PRAGMATISM at the root.

Lolita by Vladimir Nabokov. Design by Jamie Keenan. This is genius and utterly disturbing at the same time and what completes the horror is when you realise that what is creating the illusion of a girls thighs and underpants is most likely the ceiling of a girl's bedroom from a reclined perspective. Eww!

Notes of a Dirty Old Man Melzer by Charles Bukowski. Design by Pierre Mendell/ Photography by Claude Oberer. One word: spread.

The Silver Palace Restaurant by Mark Abbley. Design by David Drummond. Speaking of spread, It is not immediately obvious that this is the totally flat cover of a collection of poetry because the melting butter appears to be sitting on the top. This clever effect was achieved with a strategic spot gloss finish on a matt background. Only the melting butter has been treated and yet the whole pat jumps right off the page...even when viewed on a computer screen.