- § 361. Recent threefold scrutiny of geometrical principles
- § 362. Projective, descriptive, and metrical geometry
- § 363. Projective points and straight lines
- § 364. Definition of the plane
- § 365. Harmonic ranges
- § 366. Involutions
- § 367. Projective generation of order
- § 368. Möbius nets
- § 369. Projective order presupposed in assigning irrational coordinates
- § 370. Anharmonic ratio
- § 371. Assignment of coordinates to any point in space
- § 372. Comparison of projective and Euclidean geometry
- § 373. The principle of duality

The Principles of Mathematics was written by Bertrand Russell, and published in in 1903. It is now available in the Public Domain.