Although this edition is primarily intended for junior students, it is hoped that it may not be without interest for maturer scholars, as bringing together much scattered information illustrative of the _Academica_, which was before difficult of access. The present work will, I hope, prepare the way for an exhaustive edition either from my own or some more competent hand. It must be regarded as an experiment, for no English scholar of recent times has treated any portion of Cicero's philosophical works with quite the purpose which I have kept in view and have explained above. Should this attempt meet with favour, I propose to edit after the same plan some others of the less known and less edited portions of Cicero's writings. In dealing with a subject so unusually difficult and so rarely edited I cannot hope to have escaped errors, but after submitting my views to repeated revision during four years, it seems better to publish them than to withhold from students help they so greatly need. Moreover, it is a great gain, even at the cost of some errors, to throw off that intellectual disease of over-fastidiousness which is so prevalent in this University, and causes more than anything else the unproductiveness of English scholarship as compared with that of Germany, I have only to add that I shall be thankful for notices of errors and omissions from any who are interested in the subject. JAMES S. REID. CHRIST'S COLLEGE, CAMBRIDGE, _December, 1873._ * * * * * LIST OF ABBREVIATIONS USED IN THIS WORK. Cic. = Cicero; Ac., Acad. = Academica; Ac., Acad. Post. = Academica Posteriora; D.F. = De Finibus; T.D. = Tusculan Disputations; N.D. = De Natura Deorum; De Div. = De Divinatione; Parad. = Paradoxa; Luc. = Lucullus; Hortens. = Hortensius; De Off. = De Officiis; Tim. = Timaeus; Cat. Mai. = Cato Maior; Lael. = Laelius; De Leg. = De Legibus; De Rep. = De Republica; Somn. Scip. = Somnium Scipionis; De Or. = De Oratore; Orat. = Orator; De Inv. = De Inventione; Brut. = Brutus; Ad Att. = Ad Atticum; Ad Fam. = Ad Familiares; Ad Qu. Frat. = Ad Quintum Fratrem; In Verr., Verr. = In Verrem; Div. in. Qu. Caec. = Divinatio in Quintum Caecilium; In Cat. = In Catilinam. Plat. = Plato: Rep. = Republic; Tim. = Timaeus; Apol. = Apologia Socratis; Gorg. = Gorgias; Theaet. = Theaetetus. Arist. = Aristotle; Nic. Eth. = Nicomachean Ethics; Mag. Mor. = Magna Moralia; De Gen. An. = De Generatione Animalium; De Gen. et Corr. = De Generatione et Corruptione; Anal. Post. = Analytica Posteriora; Met. = Metaphysica; Phys. = Physica. Plut. = Plutarch; De Plac. Phil. = De Placitis Philosophorum; Sto. Rep. = De Stoicis Repugnantiis. Sext. = Sextus; Sext. Emp. = Sextus Empiricus; Adv. Math. or A.M. = Adversus Mathematicos; Pyrrh. Hypotyp. or Pyrrh. Hyp. or P.H. = Pyrrhoneôn Hypotyposeôn Syntagmata. Diog. or Diog. Laert. = Diogenes Laertius. Stob. = Stobaeus; Phys. = Physica; Eth. = Ethica.