Credit: Jamie Tufrey

The ideas followed him like ghosts all day. The mind could be desynchronised, the book asserted, and sent back, along quantum pathways in the brain, into an earlier time frame. Never forward, always back. Yet because memory is a physical function of the brain, and not an aspect of what the author called 'observational awareness', taking memories into the past remained extremely difficult.

They had to be encoded into feelings, ephemeral patterns with only the barest chance of affecting the brain in the past. Because the desynchronised state occurred among most people at least once in their lives, the phenomenon of déjà vu had a rational explanation.

Zane wasn't sure it sounded quite rational, but the idea was intriguing. He'd copied down the formal names of the chemicals and run Internet searches to determine the nature of the compounds listed in Chronocide&lt. He was not altogether surprised that they bore more than a passing resemblance to obscure derivatives of mescaline. The book had been written in the '70s, after all.

According to various websites, electrical shocks delivered in the fashion described would either cure headaches, induce a mild seizure, or do nothing at all.

And acoustic recordings of specific electronic frequencies channelled into separate headphones would either open up his mind to a new level of awareness--so claimed the New Age crowd--or have absolutely no effect whatsoever, according to the sane members of the scientific community.

It was all pseudoscience and psychotropic drugs, as he'd expected from the outset. The only remaining question, he mused, was why, if it really were just pseudoscience, did he continue to feel that it were real? In the final analysis, he realised with growing anxiety, he'd have to try the experiment himself.

The working week dragged as Zane prepared for his first attempt at time travel--or, he thought wryly, serious personal injury. Preparations were tedious and a bit more difficult than he'd anticipated, but in the meantime he'd finished the book.

Well, nearly finished the book. He'd been warned to stop at the final chapter. Apparently that one was meant exclusively for advanced time travellers.

Only read this section if you have one hundred per cent recall of everything that has happened to you in the past few days, and you have had that awareness since arriving back in time a few days ago following your experiments. Only then are you ready for the next step. Until then, none of what follows will make any sense and can only serve to dissuade you from continuing the necessary steps to get here.

He'd been sorely tempted to read it anyway, but decided to focus on first things first. He looked over the assortment of mad equipment and illegal substances in his living room. The shades were drawn, the doors locked and the telephone unplugged. His cell and PDA were in the car.

Familiarity suffused the scene. Had he truly done this before? That would explain why he was doing it now. According to Chronocide&lt, just to begin getting 'observational awareness impressions' and converting them into physical memory traces, you had to re-experience the same events at a ratio of roughly one cycle per day to the number of days travelled back in time.

The dosage of the chemical, the volume of the recordings and the level of voltage to the electrodes strapped to his head were all tuned to regress him four days. Anything farther back could cause 'end-state damage', which he still didn't understand. He suspected there would be more about it in the final chapter.

It is often difficult to determine how many times you have cycled, but do not let this disturb you. If you do not remember to change anything, the actions you are taking right now will be taken repeatedly until you cross the memory retention threshold, allowing for new action based on those future memories. Eventually, linear causality will create the conditions by which you will achieve what we could reasonably call free will.

Zane's task was to concentrate upon the day he found the book. He remembered the storm clouds approaching and the smell of impending rain. He remembered the look on the old woman's face, finding the book that led to this insane mess in his kitchen and living room.

He sat down in the chair Emily had always taken. Even after nine years, her knitting basket still sat beside it. The 'chronotropic compounds', as Mr Teel called them, waited invisibly in his tea cup, mixed with a splash of Earl Grey. Old headphones were plugged into the equally archaic tape cassette recorder. The 'inducer', which would administer the shock, sat beside the cup, its makeshift electrodes backed by first aid kit medical tape.