Which book is prefaced by All we have to decide what do with the time that given us?

The quote "All we have to decide is what to do with the time that is given to us." is from The Fellowship of the Ring, the first book in J.R.R. Tolkien's The Lord of the Rings trilogy.

It's spoken by Gandalf the Grey to Frodo Baggins, emphasizing the importance of choosing how to use the time given to them in their quest to destroy the One Ring.