The world of Jeff Wall is one of in-betweens. It is at once spectacular and mundane, dramatic and everyday; a kind of no-mans-land of the psyche. The current retrospective at Tate Modern in London presents work created over a 26 year period from 1978 to 2004. Over this time Wall has slipped seamlessly back and forth between purely fictional, cinematic images and those that are 'straight' documentary, leaving his audience slightly unsettled by the prospect that there is no boundary between the imagined world that he portrays and the real one that we experience in our day-to-day lives. Wall makes us feel that our walk to work might be a part of some grand poetic narrative that, if only we knew how, would lead us to some other realm.

Wall seems as effective in alluding to this 'other side', this kind of Narnia, whether depicting the real or the unreal. The Bridge, one of the first images in the exhibition, is at first sight a very ordinary document of the relationship between modern settlements and the natural world. It leads the viewer from the fringes of a small town in the foreground over a road-bridge and through an industrialised zone in the middle distance before drawing us beyond into a rural netherland. In contrast, Door pusher is highly constructed and dramatically lit. A man stands on one side of a closed door seemingly uncertain as to what lies on the other side. If this was a film still it would be that moment where the music lets us know that it would be unwise for him to go any further, however, he almost certainly will. Considered in relation to each other these two very different images express a similar sense of the 'other side' as being just out of reach.

An undercurrent of fear and a general uneasiness runs through much of Wall's work. More often than not there is the suggestion that something sinister lies in waiting, that there is a kind of ambiguity which leaves the viewer feeling disturbed and uncomfortable more than anything else. Ventriloquist at a Birthday Party in October 1947 appears at first to be an innocuous depiction of an everyday scene. Gradually, we notice the slight apprehension on the children's faces. The ventriloquist herself mimics the saccharin smile of a 'Stepford Wife' and her dummy's grotesque features make us wonder what kind of creature it would be if it came alive. This image is a perfect illustration of the childhood fear of things that are designed to entertain but are simply creepy.

The craft in Wall's work is immense. One image which perhaps best illustrates the intricacies of his art is A Sudden Gust of Wind (After Hokusai). One of his earliest digital montages, this work refers to a nineteenth century woodblock print by a Japanese artist and was constructed over a period of a year from 100 separate photographs. Through this long and laborious process of production Wall achieves the illusion of 'the decisive moment'. It is anything but.

Perhaps the most obvious fantasy is Flooded Grave which again is a composite of a large number of individual photographs. Created over two years it depicts 'a moment in a cemetery' when someone looks into a grave and sees the ocean floor. Once more there is this allusion to 'the other side'; again it is just out of reach. We realise that this is a fleeting hallucination and as quickly as it has appeared it will vanish.

To walk through this exhibition is as much a physical experience as a visual one. There is a strong sculptural quality to Wall's work which is almost exclusively large-scale. His use of light-boxes adds to this physicality. We are so used to seeing backlit images on our television screens and there is a resonance of that sensation when looking at these illuminated tableaux. As we move from image to image we get the feeling that we might be channel-hopping through a series of strange and surreal cable stations, each one momentarily frozen.

Wall, himself, has commented that: 'I can't draw a sharp distinction between the prosaic and the spectral, between the factual and the fantastic, and by extension between the documentary and the imaginary.' His work offers a glimpse of the intangible, the things that we cannot grasp or hold down. Wall shows us that place between the two halves of our being, between the spiritual and the everyday. He is a story-teller and a social commentator, but more than anything else, Wall is a supreme image-maker.