von Neuem means once again. He has read the book = er hat das neue Buch gelesen.

"He has read the new book" would be "Er hat das neue Buch gelesen".

By contrast, "von Neuem" means "again" or "anew". So it's actually an old book he has read for a second time.

See: http://goo.gl/OVWcu

Edit: Too late :)

or "nochmal"