In the future, earth is overcrowded, and nearly the only relief is provided by one-way teleportation to a star system several light years away, containing a rare earth-like planet. But one man is suspicious of the alleged paradise, and vows to independently investigate using his own starship, despite needing to travel for 18 years each way.

Mathematics shows up in four places. The one-way nature of the teleportation is always attributed to "Theorem One", described in quasiphysics gibberish. The smoking gun of the various suspicions is provided by an implausible periodicity hidden in an allegedly recorded-live broadcast. A bit of explanation about the use of binary in coding is engaged in. And secret communication is done by reconstructing signals sent under the noise.

The potential reader should be warned that finding a complete text of this work (all editions are out of print, but a good many are listed on http://www.abebooks.com) is not a well-defined operation. The original 1964 version was a magazine novelette. At Ace's request, Dick expanded it into a full novel, but the publisher didn't think the new material fit in with the original, so the original short version was published as part of the Ace Double series.

In 1983, the expanded version was published by Berkley. Unfortunately, a few manuscript pages were missing by then, and there are three clearly-marked gaps in the text. They later turned up, and were published in "The Philip K Dick Society Newsletter" issue #8. The missing pages can be found on-line at philipkdick.com. To add to the confusion, LIES, INC., the British edition, has its own somewhat different rewrite and missing pages saga.

One may take metafictional consolation, knowing that this textual unreliability is not only appropriate when reading Dick in general, it is even more so in this work, which has protagonists not sure what to do in the face of mutually inconsistent multiple editions of one very important book.

(At least the mathematical aspects are the same in all editions.)