The Golden Sayings of Epictetus , including the Hymn of Cleanthes. Epictetus was a Greek Stoic philosopher. Epictetus taught that philosoph was a way of life, and note purely theoretical.
This is an excellent underrated compendium of sayings from a great ancient thinker. Most are roughly a paragraph long, they range from a sentence to a page. The ebook is 206 pages long. It is a great quick read for people of all ages.