Lessons on Euclid's Elements, Book I

Table of Contents
• Lesson E1 on Absolute Geometry
• Lesson E2 on the Parallel Postulate
• Lesson E3 on Playfair's Axiom
• Lesson E4 on the Pythagorean Theorem as Euclid proved it.
• Commentary and Problems
• Supplementary Materials
• Other Systems of Axioms for Euclidean Geometry. listed on website of Robert Campbell, U British Columnbia
• Euclid's Elementas , including the Propositions, listed on website of David Joyce, Clark University.