The Infinitive of Go — John Brunner

CODE NAME POSTER

The first practical matter transmitter was a success, or so everyone thought. In spite of paranoid security restrictions, Justin Williams and Cinnamon Wright, co-inventors of the device, counted on it to revolutionise civilisation and gain them an honoured place in history.

But the first long-distance field test with a human being - a diplomatic courier carrying a vital message - somehow misfired when the courier killed himself on arrival at his destination.

To prove his faith in his invention - and to escape charges of sabotage - Justin had himself "posted" thousands of miles. He came through unchanged. It was the world that was somehow different...