Three Roads to Quantum Gravity: A New Understanding of Space, Time and the Universe is a non-fiction book by American theoretical physicist Lee Smolin.

[1][2][3] Smolin discusses three potential approaches by which a unified theory of quantum gravity, arguably the foremost issue in theoretical physics, may be realized.

But as physicist Lee Smolin writes in Three Roads to Quantum Gravity, some of the newest ideas in physics are pointing to a surprising answer: space and time do indeed appear to be made out of such atoms.

In explaining why, he offers a tour by a skilled teacher through some of the boldest and most beautiful ideas of modern science.

Smolin has been one of the leading figures in recent efforts to bring together two of the most far-reaching scientific theories of our age.—The Guardian[4]