Finalize DVD

What physically happens on a dvd when it is finalized? I know what finalizing accomplishes, but how does it do that? What on the disk is changed or added to?

[I]Computer Encyclopedia: finalization

Writing the table of contents (TOC) on a recordable CD or DVD disc. The finalization process ensures that the disc can be played back on most CD and DVD players. See disc-at-once.


Thanks. That makes sense.
How can the drive that created the dvd read it without a TOC?