Kenneth S. Williams is currently Professor Emeritus and Distinguished Research Professor of Mathematics at Carleton University, Ottawa.

• Preface; 1. Joseph Liouville (1809–1888); 2. Liouville's ideas in number theory; 3. The arithmetic functions σk(n), σk*(n), dk,m(n) and Fk(n); 4. The equation i2 + jk = n; 5. An identity of Liouville; 6. A recurrence relation for σ*(n); 7. The Girard–Fermat theorem; 8. A second identity of Liouville; 9. Sums of two, four and six squares; 10. A third identity of Liouville; 11. Jacobi's four squares formula; 12. Besge's formula; 13. An identity of Huard, Ou, Spearman and Williams; 14. Four elementary arithmetic formulae; 15. Some twisted convolution sums; 16. Sums of two, four, six and eight triangular numbers; 17. Sums of integers of the form x2+xy+y2; 18. Representations by x2+y2+z2+2t2, x2+y2+2z2+2t2 and x2+2y2+2z2+2t2; 19. Sums of eight and twelve squares; 20. Concluding remarks; References; Index.

'This is the only book in English entirely devoted to the subject and is thus an extremely valuable resource for both students and researchers alike.' Mathematical Reviews