I had just sat down to begin this review on my laptop when the doorbell went. I wasn't expecting anyone. It was probably going to be one of those pitiful door to door salesmen trying to get me to buy a dishcloth for a fiver. They make me feel so bad. But it wasn't. I opened the door and looked at myself. It was me. 
 "Huh, what? " I said. "You're... you're..." 
 "Yeah, that's right. I'm you. Sorry about that. Like looking in a mirror, isn't it? But worse!" 
 "Uh... what's goin' on ?" This was bad, I was quoting Marvin Gaye album titles now. 
 "May I come in?" I said 
 "Well, I suppose so," I said. So I went inside. I made myself a cup of tea and one for me too. We sat down at the table and regarded each other with frank horror. 
 "I don't really look like that, do I?" I was looking kind of rough. "What's this all about? Are you a clone?" 
 "No, I'm the one and only you, that's to say I'm me all right. I'm from the future. 26th of November 2012 to be precise." 
 "Oh you think I'm going to believe that?" I raised my eyebrows in a hauty sceptical manner. "I just read a book about time travel. It's that one there - " I gestured to the fat wedge on the table between us. "In fact I was just about to review it." 
 "Stephen King's 11.22.63 - yes, that's the reason I'm here." 
 "Huh?" 
 "I'll come to the point, PB. " My eyes narrowed almost to the point where I couldn't see out of them. "You can't write that review. The one you were going to. You have to change it." 
 "What do you mean, change it? How do you know what I was going to write, anyway, I haven't written it yet?" 
 "Because I wrote it, remember? I'm you. Come on, the guy in this book is a lot quicker on the uptake than this. I haven't got all day." I could be a bit snappy sometimes. "You were all set to launch into one of your famous diatribes weren't you? You'd already worked up a few choice phrases, along the lines of 
 So he goes back in time to 1958 and he's living through these years waiting to get to the assassination bit and that's where the story becomes this I-Love-The-Late-50s-Stroke-Early-Sixties loveletter from Stephen King to his own childhood. The boring teacher gets to meet a girl and fall in lurve, sweet sweet lurve. That's not a spoiler, it's in the blurb, sweet sweet blurb. He gets to live in The perfect Small Town. He gets to Affect Kids' Lives. He gets to Feel Alive For The First Time and swear he's never going back to the Future again! He gets to blurt out anachronistic slang and have people look at him funny! He gets to wince at casual racism! It's all good. But not for me. I wanted to get back to Oswald. I paid my damn ticket, and I wanted to see some Oswald. The ticket did not say GREASE IS THE WORD on it. But for 200 pages it may as well have. But Oswald's the one that I want. Oooh ooh ooh. 
 I was amazed - that was exactly what I was going to write. 
 "So as usual you were going to be so mean. You can't deny it. I know you were because you did it, that's to say I did it, and I'm here now to stop myself from doing it." 
 "Okay so let me get this straight, you came from the future - howja do that anyway?" 
 "There's a portal in next-door's garden shed. I got the idea of looking for a portal when I read this book." 
 "Oh - anyway, you came from the very near future and you decided the most important thing to do was to stop me writing one particular review on Goodreads of one dubious Stephen King novel? Why didn't you do something more useful than that? " 
 "Well, I did," I whined. "I already prevented Kate Middleton from falling downstairs at Buckingham Palace - that was tough, you know the past doesn't want to be changed. And I found somebody's lost cat for them. And now you - you're the last on my list." 
 "So what's the big deal about my review of 11.22.63?" 
 "Well, you read the thing, so you know about the Butterfly effect, right?" 
 "Er, yes. Stephen King goes on and on and on about it." 
 "Well, there you are. Because of that." 
 "I don't get it." 
 "Well, like that song You can't move forward without movin back" 
 "I've never heard of that." 
 "Oh of course - that's from three weeks in the future. Sorry about that, I gave myself away there." 
 "No you didn't, you already told me you're from the future." 
 "Oh yes, so I did. It can be confusing getting all this straight in your head when you're from the future. Got any aspirin? Anyway, your nasty review gets to be unaccountably popular on Goodreads." 
 "Oh yeah, it does? As popular as The Wind-Up Bird Chronicle? " 
 "More than that." 
 "Great!" 
 "No, not great." 
 "But I need another hit. I've been getting kind of middling results for months. You're only as good as your last review, you know. It's a vicious world. No compassion. " 
 I was quoting old Talking Heads song titles, but this was a once in a lifetime thing that was happening. So that made it okay. 
 "Yeah well, that's the problem. After your review things... happen. If your review persuades just one single person not to buy the book, then that's probably why in three weeks' time Japan splits in half and most people have got acne in the world of three weeks from now. The future is important, it must be preserved. Hosts of butterflies are always in the air, waiting to fly around like crazy ass future-changing bastards." 
 "That's ridiculous." 
 Suddenly we heard the front door opening. 
 "That'll be Helen, she's usually back from work at this time." 
 "Ah, I'd forgotten. This will be awkward. Isn't there any place for me to hide? " 
 "Er, no - this is just a normal living room, as you know, since it's yours. You could try to hide behind the settee but you'll have to shove it out from the wall, and she'll notice I think." 
 It was too late. She came into the room and surveyed the both of us. 
 "This is a bit weird. He's me but he's from the future." 
 She didn't miss a beat. 
 "Oh well, you've just come in time. I need you to pick up Georgia from school, she had a rehearsal for the play so I couldn't do it, and can you (pointing at the future me) nip to Sainsbury's and get me a few things? I need you to be quick, I'm in a mad rush. I've got that thing tonight, remember?" And she gave me a shopping list. 
 I looked at me. "Is this kind of thing allowed? Now we're doing Multiplicity." 
 "Oh yes, that old film with Michael Keaton. That was quite good. Yes, well, I suppose this once. But look - you have to give 11.22.63 three stars. Remember Japan and acne." 
 "Okay, I promise." 
 That's the last I saw of me until I got curious about whether there really was a portal in the neighbour's garden shed.