"Rollback"

Coming April 3, 2007 from Tor Books: Robert J. Sawyer's Rollback.

From the author's website:

The aliens have sent us a message, and we have responded.

Dr. Sarah Halifax decoded the first-ever radio transmission received from aliens. Thirty-eight years later, a second message is received — and Sarah, now 87, may hold the key to deciphering this one, too ... if she lives long enough.

A wealthy industrialist offers to pay for Sarah to have a rollback — a hugely expensive experimental rejuvenation procedure. She accepts on condition that Don, her husband of sixty years, gets a rollback, too. The process works for Don, making him physically twenty-five again. But in a tragic twist, the rollback fails for Sarah, leaving her in her eighties as the second message arrives.

While Don tries to deal with his newfound youth and the suddenly vast age gap between him and his wife, Sarah struggles to do again what she'd done once before: figure out what a signal from the stars contains....