A first-century Stoic, Epictetus argued that we will always be happy if we learn to desire that things should be exactly as they are. His Enchiridion, or Manual, is a distillation of his teachings and an instructional manual for a tranquil life as it offers guidelines for those seeking contentment. Unabridged republication of the Enchiridion as published by A. L. Burt, New York, [n.d.].
Nicomachean Ethics by Aristotle Enduringly profound treatise, whose lasting effect on Western philosophy continues to resonate. Aristotle identifies the goal of life as happiness and discusses its attainment through the contemplation of philosophic truth.
Meditations by Marcus Aurelius Stirring reflections on the human condition provide a fascinating glimpse into the mind and personality of a highly principled Roman warrior and emperor of the 2nd century.
The Republic by Plato Influential philosophical treatise of 4th century BC chiefly concerns the idea of justice, plus Platonic theories of ideas, criticism of poetry, philosopher's role. Source of the cave myth. Jowett translation.