SECOND THOUGHTS / Quays of the kingdom: Iain Sinclair follows the river back to the source of his second novel, Downriver (Grafton pounds 5.99)

DOWNRIVER was one of my more interesting mistakes. What an innocent, a dupe] I hadn't bothered to learn the first rule: never, ever, admit in advance what a book will be about. (How could you know?) This does, I confess, put raising an advance on a par with raising the Titanic. The gimmick is to keep a stockpot of potential titles on the boil. Jot them down as they pop into your head, short and snappy or minatory and oblique. Develop a folder of spurious outlines, plots that will never mature. Keep them at your elbow like a flask of frozen embryos.

You can always sell a good title. Then you can write whatever comes into your head. Editors are far too busy to actually read these things. They delegate. To anyone who is hanging around the office, some rep or phone-cleaner. Keep them waiting long enough and they'll be pathetically grateful for any scrap of paper. The wretched functionary who commissioned your original synopsis will certainly have been rationalised by now, booted into the street, and - if he or she is any good - surfaced at some other conglomerate. They'll be foaming at the bit to buy the same yarn again, under yet another title.

It was the river that hooked me. The river seen through the window of a train.

The Thames had been off the agenda far too long. It's the lifeblood, the torpid spine, the dream-chute of the city. It obsessed me. It was thick with the auditioning voices of the almost dead, prophetic whispers focused by earlier, finer writers: Conrad, Eliot, Dickens, as well as that literary underclass populated by such spectres as Sax Rohmer's Moris Klaw. Competing ideologies rippled along the shoreline in an unresolvable Manichean conflict. They threw up miraculous anomalies, zones of surreal savagery. Greed spat out its glittering towers to shine above the swamplands of entropy.

It was all too easy. I had only to cultivate the speed to accept the dictation of these furies. Every bend in the river offered a fresh witness. Arriving in Tilbury on a promise from Granta (and with the firm belief that if a story is worth selling once, it must be worth selling twice), I walked out of the station into a narrative that screamed to be transcribed. The town was a posthumous fiction. The stuff was lying everywhere like contraband cargo. I was in the wrong place at the right time. Tilbury Riverside, with its abandoned cathedral of a station, its decaying wharfs, was the capital of wrongness. I spent all that remained of my advance on railway tickets out of Fenchurch Street. There was no turning back. My pious hopes of 'redeeming' with this text certain dubious aspects of my first novel, White Chappell, Scarlet Tracings, were lost in a hellish babel of competing voices.

That is what all writing seems to be: waiting, listening, smothering the cruel logic of conditioned reflexes.