The Rule of Four has 384 pages.
It depends on what size font and page is used.
Rule of the Bone has 320 pages.
Wizard's First Rule has 836 pages.
Four Quartets has 40 pages.
Ball Four has 371 pages.
And Four to Go has 190 pages.
The Four-Story Mistake has 177 pages.
The Four-Headed Dragon has 180 pages.
The Four-Dimensional Nightmare has 208 pages.
The House of the Four Winds has 318 pages.
Four Moons of Darkover has 284 pages.
Four Steps to Death has 207 pages.