Between 1645 and 1650, Dury wrote a great many tracts on improving the Church and society.  These include an as yet unpublished one, dated 16 August 1646, giving his views on the post of library keeper at Oxford.  The poor state of Oxford’s library led Dury to observe that the librarian is to be “a factor and trader for helpes to learning, a treasurer to keep them and a dispenser to apply them to use, or to see them well used, or at least not abused."[5] During his travels on the Continent, Dury had visited Duke Augustus of Brunswick and was obviously very impressed by the great library the Duke was assembling at Wolfenbuttel.  In his important Seasonable Discourse of 1649 on reforming religion and learning, Dury had proposed establishing in London the first college for Jewish studies in the modern world.  In this proposal, he saw as a basic need the procurement of a collection of Oriental books.  Such a library was not just to store materials, but to make them available and thereby increase knowledge.  Hartlib, in a pamphlet entitled Considerations tending to the Happy Accomplishment of England’s Reformation in Church and State, written in 1647 and published in 1649, had proposed a central “Office of Addresse,” an information service dispensing spiritual and “bodily” information to all who wished it.  The holder of this office should, he said, correspond with “Chiefe Library-Keepers of all places, whose proper employments should bee to trade for the Advantages of Learning and Learned Men in Books and MS[S] to whom he may apply himselfe to become beneficiall, that such as Mind The End of their employment may reciprocate with him in the way of Communication” (p. 49).

Events surrounding the overthrow and execution of Charles I led Dury to become more personally involved in library matters.  After the king fled from London, the royal goods were subject to various proposals, including selling or burning.  These schemes of disposal extended to his books and manuscripts, which were stored in St. James’s Palace.  John Selden is credited with preventing the sale of the royal library.  Bulstrode Whitelocke was appointed keeper of the king’s medals and library, and on 28 October 1650 Dury was appointed his deputy.  According to Anthony a Wood, Dury “did the drudgery of the place."[6] The books and manuscripts were in terrible disorder and disarray, and Dury carefully reorganized them.  As soon as he took over, Dury stopped any efforts to sell the books and ordered that the new chapel, built originally for the wedding of King Charles I, be turned into a library.  He immediately ordered the printing of the Septuagint copy of the Bible in the royal collection.

In the same year that he became deputy keeper, Dury wrote the following tract, one of a dozen he composed in 1650 on topics ranging from the educational to the ecclesiastical.  Among the latter was his introduction to Thomas Thorowgood’s book contending that the American Indians are descended from the Israelites, a work that also served as promotional material for New England colonization.