ERRATA Vol. I Page 99, line 3 _for_ 149-80 _read_ 149-60. Page 99, line 22 _for_—and to be “suggested,” not signified _read_—instead of being only suggested. Page 100, line 10 _for_ hearing _read_ seeing. Page 103, note, lines 5, 6 _for_ pp. 111, 112 _read_ p. 210. Page 200, note, line 14 _for_ Adam _read_ Robert. Page 364, line 8 from foot _for_ and _read_ which. Page 512, note 6, line 3 _for_ imminent _read_ immanent. Vol. II Page 194, note, line 3 _for_ Tyndal _read_ Tindal. Page 207, line 1, insert 13. before _Alc._. Page 377, line 6 _for_ antethesis _read_ antithesis. Vol. IV Page 285, lines 4, 5 _for_ Thisus Alus Cujus, &c. _read_ Ursus. Alus. Cuius. &c. The inscription, strictly speaking, appears on the Palace of the Counts Orsini, and is dated MD. COMMONPLACE BOOK. MATHEMATICAL, ETHICAL, PHYSICAL, AND METAPHYSICAL Written At Trinity College, Dublin, In 1705-8 _First published in 1871_ Editor’s Preface To The Commonplace Book Berkeley’s juvenile _Commonplace Book_ is a small quarto volume, in his handwriting, found among the Berkeley manuscripts in possession of the late Archdeacon Rose. It was first published in 1871, in my edition of Berkeley’s Works. It consists of occasional thoughts, mathematical, physical, ethical, and metaphysical, set down in miscellaneous fashion, for private use, as they arose in the course of his studies at Trinity College, Dublin. They are full of the fervid enthusiasm that was natural to him, and of sanguine expectations of the issue of the prospective authorship for which they record preparations. On the title-page is written, “G. B. Trin. Dub. alum.,” with the date 1705, when he was twenty years of age. The entries are the gradual accumulation of the next three years, in one of which the _Arithmetica_ and the _Miscellanea Mathematica_ made their appearance. The _New Theory of Vision_, given to the world in 1709, was evidently much in his mind, as well as the sublime conception of the material world in its necessary subordination to the spiritual world, of which he delivered himself in his book of _Principles_, in 1710.