In 1693-94 she was in correspondence with John Norris concerning his theory that God should be the sole object of human love. So acute, so devout, so ably expressed, were Miss Astell's letters that Mr. Norris won her consent to an anonymous publication of the correspondence in 1695 under the title, _Letters concerning the love of God_. In his Preface Dr. Norris said that he could not express the value he set upon Miss Astell's letters either as to their ingenuity or their piety, "the former of which might make them an entertainment for an angel, and the latter sufficient (if possible) to make a saint of the blackest devil." He said he had never met any discourses that had so enlightened his mind and enlarged his heart, had so taken possession of his spirit, and had exerted such "a general and commanding influence over his whole soul." While carrying on this discussion with Mr. Norris another subject had been more definitely occupying Miss Astell's active mind, and in 1694 she had published her most original and important work, _A Serious Proposal to the Ladies for the Advancement of their true and greatest interest_. This appeared in July, 1694, and by 1697 the fourth edition came out. "By a Lover of her Sex" was the only indication of authorship. In 1700 she published _Some Reflections upon Marriage_, a discussion based on the unhappy experiences of her neighbor in Chelsea, the Duchess of Mazarine. The years 1704-05 show her greatest activity. In _Moderation Truly Stated_ (1704) she answered Owen's _Moderation a Virtue_, and in the Preface discussed Davenant's recently published _Essays on Peace and War_. In _A Fair Way with Dissenters and their Patrons_ (1704) she attempted to answer Defoe's _Shortest Way with Dissenters_, while in a Postscript she carried on her analysis of Owen's views on Moderation. In _An Impartial Enquiry into the Causes of Rebellion and Civil War in this Kingdom_ she took up another phase of politics--religious controversy, showing herself a believer in Stuart doctrines of Church and State. _The Christian Religion as Profess'd by a Daughter of the Church of England_ (1705) showed the insidious dangers of latitudinarianism and deism within the Church, and defended the Christian religion as reasonable and resulting in moral excellence. In 1709 appeared her last pamphlet, _Bart'lemy Fair, or an Enquiry after Wit_, an attack on Shaftesbury's _Letter Concerning Enthusiasm_, which she, however, wrongly attributed to Swift. The Preface to _Bart'lemy Fair_ is a bitter invective against the Kit-Kat Club.