Graceful， succinct prose and engaging illustrations trace the evolution of life on Earth out of the blue and back again。

Clear and inviting nonfiction prose， vetted by scientists—together with lively illustrations and a time line—narrate how life on Earth emerged “out of the blue。” It began in the vast， empty sea when Earth was young。 Single-celled microbes too small to see held the promise of all life-forms to come。 Those microbes survived billions of years in restless seas until they began to change， to convert sunlight into energy， to produce oxygen until one day—Gulp！—one cell swallowed another， and the race was on。 Learn how and why creatures began to emerge from the deep—from the Cambrian Explosion to crustaceans， mollusks to fishes， giant reptiles to the rise of mammals—and how they compare to the animals we know today， in a lively and accessible outing into the prehistoric past that boils a complex subject down to its lyrical essence。