The Dark is Rising by Susan Cooper, 1973

Will Stanton learns he's the last of the Old Ones on his eleventh birthday and thus, has special powers and responsibilities. Additionally, he learns that he's the Sign Seeker, which means he must go on a quest to find the six signs. When he has collected the six signs (wood, bronze, iron, fire, water, stone), the power of the Dark will be lessened for a time and the Light will have a strong weapon against the Dark in the final battle. Newbery Honor book.