The Rowan

The Rowan is the first book in the Rowan series by Anne McCaffrey.

Warning: Wikipedia contains spoilers

The Rowan is set in a backdrop of a technologically advanced society in which telepathy, telekinesis and other psionic powers have become scientifically accepted and researched. Telekinetic and telepathic powers are used to send spaceships through space, thus avoiding the lightbarrier and allowing for the colonization of other star systems.

In the series psionic powers occur of varying strength, the possessors being ranked from T12 (the weakest) to T1 (the strongest). The very strongest are employed as "T1 Primes" by an independent company FT&T for teleporting cargo and passengers between the systems. The Rowan tells the life story of a young orphan, of T1 talent, from the moment the child's community is wiped out in a flood to the time when she becomes a Prime and after a life of loneliness falls in love with a previously undiscovered T1 in a far away star system being attacked by aliens.

The central section of the book is based on McCaffrey's earlier short story Lady in the Tower.