On What Matters is by Derek Parfit. The Oxford University Press 2 volume set has 1440 pages. It is a philosophy textbook.
Why Orwell Matters has 211 pages.
Celestial Matters has 348 pages.
Why Truth Matters has 215 pages.
Race Matters has 159 pages.
When Nothing Else Matters has 448 pages.
Water Sleeps has 470 pages.
After Many a Summer has 314 pages.
2500 pages are approximately 2,500 pages.
There But For The has 357 pages.
We Who Are About To... has 170 pages.
If I Did It has 208 pages.
What Is the What has 475 pages.