Startide Rising (The Uplift Saga, Book 2)

David Brin's Uplift novels are among the most thrilling and extraordinary science fiction ever written. Sundiver, Startide Rising, and The Uplift War--a New York Times bestseller--together make up one of the most beloved sagas of all time. Brin's tales are set in a future universe in which no species can reach sentience without being "uplifted" by a patron race. But the greatest mystery of all remains unsolved: who uplifted humankind?
The Terran exploration vessel Streaker has crashed in the uncharted water world of Kithrup, bearing one of the most important discoveries in galactic history. Below, a handful of her human and dolphin crew battles armed rebellion and a hostile planet to safeguard her secret--the fate of the Progenitors, the fabled First Race who seeded wisdom throughout the stars.