Front Cover -- Ingenuity In Mathematics -- Copyright Page -- Contents -- Preface -- Essay 1. Probability and π -- Essay 2. Odd and Even Numbers -- Essay 3. Sylvester's Problem of Collinear Triads -- Essay 4. The Algebra of Statements -- Essay 5. The Farey Series -- Essay 6. A Property of an -- Essay 7. Squaring the Square -- Essay 8. Writing a Number as a Sum of Two Squares -- Essay 9. The Isoperimetric Problem -- Essay 10. Five Curiosities from Arithmetic -- Essay 11. A Problem of Regiomontanus -- Essay 12. Complementary Sequences -- Essay 13. Pythagorean Arithmetic -- Essay 14. Abundant Numbers -- Essay 15. Mascheroni and Steiner -- Essay 16. A Property of Some Repeating Decimals -- Essay 17. The Theorem of Barbier -- Essay 18. The Series of Reciprocals of Primes -- Essay 19. Van Schooten's Problem -- Solutions to Exercises -- Bibliography -- Back Cover.