When an author such as Roberta Gellis returns to her science fiction roots and takes to the space waves, a lot fans will sit up and take notice. Our reward is a dilly of a space adventure, reminiscent of those science fiction days of yore. IMPERIAL CHALLENGE (4) introduces Cyn, a former free trader who is determined to swap his risky lifestyle for the safety and stability of service as an interstellar mailman, even if he has to battle pirates, spies and conspiracies along the way. The result is pure fun for lucky readers as the irrepressible hero manages to come up trumps, win the girl and save the day. Look for this delightful beginning to the Overstars Mail series at www.starpublications.com in August.