515 pages....thats what my resources say at least
The Gate House has 688 pages.
The Lost Gate has 384 pages.
The Seventh Gate has 368 pages.
Peril's Gate has 721 pages.
A Gate at the Stairs has 322 pages.
The Hour of the Gate has 304 pages.
The Gate of Time has 176 pages.
The Mandelbaum Gate has 330 pages.
Rider at the Gate has 437 pages.
The Goblin Gate has 384 pages.
Wide Is the Gate has 751 pages.
The Fiftieth Gate has 339 pages.