The final book of the Problems contains eleven chapters dealing with complexion, and especially skin color. Nearly half discuss the effects of the sun on complexion (1, 6–8, 11), and three others the influence of various forms of exercise on complexion (3–5). One chapter is on the hair color of those who work on the sea (2), and one on the skin color of those who work with grain (10). There is one chapter on the effects of old age on complexion (9). Four chapters (3, 6–8) are clearly raising questions about passages in the works of Theophrastus.