This isn't a review, it's a love letter. Sorry.
In the large and disparate family of Iain Banks novels this is the funny looking kid whom you're sure must be adopted. Yes, it has its daddy's eyes and a wicked grin, but it's... Different. It's not one of the truly creatively nasty ones (The Wasp Factory; Complicity). It's not one of the warm(ish)-hearted ones (The Crow Road; Whit; The Quarry). It's not one of the dark, bleak, mildly baffling ones (Canal Dreams; A Song of Stone), or a love story with complications (Stonemouth; Dead Air; The Steep Approach to Garbadale). It's not Banks-with-an-m, though a knife missile does put in an appearance at one point. It's something altogether stranger, and unmistakably Banks.
(Apologies to Walking On Glass, The Business, and Transition, I haven't forgotten you, honest. As to Espedair Street, well, we haven't yet been introduced. I look forward to making your acquaintance.)
Banks's other books are grounded more-or-less firmly in some kind of reality; this is not. The Bridge is an extended dream sequence...
STOP!
I know what you're going to say, and:
1/ That's not a spoiler, it's mentioned quite explicitly in the blurb.
2/ It's not some kind of wishy-washy, misty-eyed, hand-wavingly vague, delicately allusive, oh-look-at-me-I've-read-a-psychology-textbook dream sequence with lots of notional fog drifting about the place, and sudden and jarring transformations, but something much more solid and robust.
The Bridge is an extended dream sequence in which three main strands of narrative reflect and inform one another. It has the lightness of The Business (see, I told you I hadn't forgotten you), and a much larger dose of verbal dexterity. It is, to be frank, very, very funny with serious undercurrents. It's a puzzle-box, and one of the delights is unpacking it for yourself.
Now, why might you not enjoy it?
Well, and this made my heart sink when I encountered it, but one of the strands is written in the kind of bizarre phonetic spelling that stopped me from reading Feersum Enjinn. I got used to it. Do not skip these sections, they are genuinely hilarious. I wonder if this is where Pratchett got the Feegles from.
There is the whole dream thing to contend with, but I think I've covered that. It's not as if there's that much gratuitous weirdness.
There's a fair bit of sex, so if you're one of Bertie Wooster's aunts... Well, probably just Aunt Agatha, Aunt Dahlia would take it in her stride, don't you think? Probably has done in her time... You might want to look away. Mind you, if you have a problem with sex you'll probably want to steer clear of Banks altogether.
There's the fact that it's not pure fantasy: one of the strands, and hence about a third of the book, is memory, and set in 60s-80s Scotland (roughly). In fact it's not pure anything, which is perfectly fine by me, but may bother you.
Oh, and there's the possibility that you may be expecting something deep and chin-strokingly serious, in which case you won't like the surface glitter... did I mention that it's really very funny? I did? Oh good. That and that if you are the kind of person who drives themselves mad trying to figure out what each and every reference means then you'll need a padded cell by the end. It might even be worth it.
This leaves me with the ticklish problem of the K-word and, slightly less contentiously, the matter of the G-word. There are, in the bridge section itself, traces of Kafka, and shades of Gormenghast. Both are powerful spices used sparingly, and I doubt I'd have spotted it if I hadn't read Walking On Glass, but they are there. Don't expect heavy and paranoid.
Just to complete this game of Iain Banks bingo, and with due apologies to anyone on the wrong side of the Atlantic, where Transition is Banks-with-an-m, there may be a touch here of the conflict between realism and solipsism - don't ask me about that, I'm no philosopher.
Bingo!