What makes a book a classic?

A classic work is an expression of art, life and beauty, according to About.com. The work is a reflection of the time period during which it was written, and it stands the test of time.

Classic books are themed around universal human experience. They are written to illicit primary emotional responses and are centered around themes such as love or hate that are understood across a broad age and experience spectrum. Classic works of literature make connections between other writers or works that contain universally accepted truth or wisdom. Classic works have information about history that are either implied or directly referenced within the work itself.