The first fruitful works of Greek botany. Theophrastus from Eresos in Lesbos, born around 370 BC, is the author of the most significant botanical works that have survived from classical antiquity. He was a student, collaborator, and successor of Aristotle. Like his predecessor, he had an interest in all aspects of human knowledge and experience, particularly in the natural sciences.

His writings on plants contrast with Aristotle's zoological works. In the Inquiry into Plants, Theophrastus classifies and describes varieties—covering trees, plants of specific regions, shrubs, herbs, and grains. In the last of the nine books, he focuses on the juices of plants and the medicinal properties of herbs.

This edition is in two volumes; the second contains two additional treatises, On Aromatics and On Signs of the Weather. In the work De causis plantarum, Theophrastus turns to the physiology of plants. Books 1 and 2 deal with birth, growth, flowering, and fruiting, as well as the effects of climate. In Books 3 and 4, he studies cultivation and agricultural methods. In Books 5 and 6, he discusses plant reproduction, diseases and other causes of death, as well as distinct flavors and aromas.

The Loeb Classical Library edition is in three volumes. The famous Characters of Theophrastus are of a completely different character. This collection of descriptive sketches is the earliest known writing of characters and a striking reflection of contemporary life.