There's a certain kind of writer who should be allowed to grow old only if he promises to do it disgracefully. Many of Hanif Kureishi's fans would argue that he belongs to this group, and perhaps some of the disappointment that a faithful Kureishi reader feels when reading Something To Tell You stems from the fact that this is such a neatly wrapped, conventional, sedate novel.   Something To Tell You could be seen as the bookend to Kureishi's Buddha of Suburbia. It features a similar laundry list of characters, ranging from the eccentric to the forceful to the lost, drifting through the landscape of Britain's suburbia. Many of Kureishi's characters are either deeply seductive or determinedly mundane, caught in political causes or domestic dramas that are large enough to encompass and engulf their lives. In this novel, Kureishi's sixth, he stirs so much into the mix that what emerges is a thick soup where no particular ingredient stands out.   The central character is Jamal Khan, psychoanalyst: 'Like a car mechanic on his back, I work with the underneath or understory: fantasies, wishes, lies, dreams, nightmares—the world beneath the world, the true words beneath the false… At the deepest level people are madder than they want to believe.' It's promising stuff, but the story unfolds in predictable ways. Jamal has his own secret, one so dark that when he unburdened himself to his own analyst, the experience was classically cathartic, unleashing floods of shit and vomit in the aftermath of the session. As Jamal, now middle-aged, looks back to the world of 1970s suburbia, where his personal tragedy is set, Something To Tell You flashes into beguiling life every so often. Jamal may be the quintessential dull character made interesting by circumstance, but many of the people who surround him are fascinating — Kureishi has a master's eye for speech, dialogue and the quirks of the individual, and there's much to hold the reader's attention. There's Jamal's tattooed-and-pierced sister Miriam, a cameo appearance by Karim from The Buddha of Suburbia, and another by Omar Ali, now 'Lord' Ali, from My Beautiful Laundrette. Karim discusses the negatives of being on Celebrity; Ali is now one of the smooth millionaires who mushroomed in Tony Blair's warmth. Jamal's London is as detailed as ever, from the unlimited menu of sexual possibilities to the children's school that comes recommended by Mick Jagger.   It's when ...