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Blurb: “The Dirac Transmitter: key to space - and time.
The new communications device had one huge advantage over ultrawave or the faster-than-light ships that still took months to carry a message from Earth to the outlying worlds. Its transmissions could be picked up instantly, anywhere in the Universe.
With an expanding interstellar empire to administer, Captain Robin Weinbaum reckoned his job would become a whole lot easier.
Until the impossible happened. Someone started monitoring the Dirac transmissions - before they were made.”