Voyager by Diana Gabaldon

Their passionate encounter happened long ago by whatever measurement Claire Randall took. Two decades before, she had traveled back in time and into the arms of a gallant eighteenth-century Scot named Jamie Fraser. Then she returned to her own century to bear his child, believing him dead in the tragic battle of Culloden. Yet his memory has never lessened its hold on her... and her body still cries out for him in her dreams.

Then Claire discovers that Jamie survived. Torn between returning to him and staying with their daughter in her own era, Claire must choose her destiny. And as time and space come full circle, she must find the courage to face the passion and pain awaiting her...the deadly intrigues raging in a divided Scotland... and the daring voyage into the dark unknown that can reunite or forever doom her timeless love.