||Most of Epicurus' writings are lost, but book ten of Diogenes Laertius' Lives of Eminent Philosophers, in its summary of Epicurus' life and teachings, contains three letters by Epicurus that summarize his physics, views on celestial and meteorological phenomena, and ethics. It also includes the "Principal Doctrines," short sayings mainly on ethics. The Roman poet and fervent Epicurean Lucretius (c. 94-55 BCE) composed "On the Nature of Things," a massive 6-book summary of Epicurean physics. The Roman statesmen Cicero (106–43 BCE) includes important summaries of Epicurean arguments in his philosophical works. Long & Sedley 1987 and Gerson 1994 are compendiums of many of the crucial texts, with Long & Sedley 1987 including extensive commentary.