Surprised by Joy: The Shape of my Early Life is an autobiography written by C.S. Lewis in 1955. The book overall contains less detail concerning specific events than a typical autobiography. This is because Lewis' purpose in writing about his life was not primarily for historical purposes; instead, his aim was to identify and describe the events surrounding his accidental discovery of and consequent search for the phenomenon he labeled Joy, a word that was the best translation he could make of the German idea of Sehnsucht, or longing. That is not to say that the book is devoid of information about his life. On the contrary, Lewis recounts and remembers his early years with a measure of amusement sometimes mixed with pain. However, while he does describe his life, the principle theme of the book is Joy.

The book's last two chapters cover the end of his search as he makes the leap from atheism to theism and then from theism to Christianity. Lewis ultimately discovers the true nature and purpose of Joy and its place in his own life. Ironically, the woman that he was to marry was named Joy (Gresham).