In Book III, he describes how ideas and propositions are expressed in words and language. The printing history of the first edition was the subject of queries and responses in Bibl.
Finally, in Book IV, he discusses knowledge, the degrees of knowledge and opinion, and the limits of human understanding.
The new material was also issued on slips for insertion in copies of the 1st edition.
London, printed for Thomas Dring ; and Samuel Manship , M DC XCIV  , 407,  p. New material includes 8 (the Molyneux problem), II.xxviii ( Of identity and diversity), a revised ( Of power) and an analytical index; the Epistle to the Reader contains an answer to Lowde 1694 (item #436). 83 (headed Copia A [the insertions] and T [complete copies]) and MS.
This I proposed to the Company, who all readily assented; and thereupon it was agreed, that this should be out first Enquiry.
Some hasty and undigested Thoughts, on a Subject I had never before considered, which I set down against our next Meeting, gave the first entrance into this Discourse, which having been thus begun by Chance, was continued by Intreaty; written by incoherent parcels; and, after long intervals of neglect, resumd again, as my Humour or Occasions permitted; and at last, in a retirement, where an Attendance on my Health gave me leisure, it was brought into that order, thou now seest it. Some of the /incoherent parcels still survive, allowing us to trace the development of the work. The textual history of the early editions is described by C. Johnston, The printing history of the first four editions of the Essay concerning human understanding / by Charlotte S. New material: II.xxiii ( Of the association of ideas) and ( Of enthusiasm), as well as additions to 26 and 6. Lockes contract with Manship and the Churchills is preserved in MS. There are two states of the title page of this issue, the difference being in the address of Samuel Manship: one version has at the Black Bull and the other has At the Ship; another issue, with a cancel title leaf: London, printed for Awnsham and John Churchil , and Samuel Manship, M DC XCIV . 51, headed Copys 94. The portrait of Locke is subscribed M 230 An essay concerning humane understanding. London: printed for Awnsham and John Churchil , and Samuel Manship , 1695. Shortly thereafter, he signed an agreement with Thomas Bassett to publish the book, which duly appeared in December 1689 (although the publisher gave the date 1690 on the title page). In Book I, Locke establishes that our ideas are not innate. In Book II, he goes on to show that ideas are the result of experience, of sensation and the minds reflection upon its experiences. Vertue sculp. Y 68; J 39; C 92 236 An essay concerning human understanding. A second state corrects the typo ( Witten); title page of vol. In the late 1690s he began a new final chapter on the conduct of the understanding. This was never incorporated into the Essay, but was published separately by his literary executors in 1706. Dedication to Thomas Herbert, Earl of Pembroke, is signed John Locke. The first edition was ready for distribution in late November 1689; Locke received his bound copies on December 3, 1689 (MS. The logical next step, having argued that certain knowledge of the laws of morality is attainable, would have been a treatise on ethics.