His major writing was a work intended as direction for an unnamed anchoress. It is known under the title The Ladder of Perfection.
Interstingly, Hilton freely admitted in his journals that he never personally experienced the familiarity with God that he describes as the goal in his writings. This has not deterred many generations of others who came after him from learning much about devotion and the mystical way from his counsel.
Here is a small sample of the Ladder for you to read Don't let the old english scare you away, once you get past the clunky word forms it is really a beautiful passage about practicing virtues:
CHAPTER XIII: How Virtue beginneth in Reason and Will and is perfected in Love and Liking, or Affection
THUS have I told thee a little of Contemplation what it is, to the intent that thou mightest know it and set it as a mark before the sight of thy soul, and to desire all thy lifetime to come to any part of it by the grace of our Lord Jesus Christ. This is the conforming of a soul to God, which cannot be had unless it first be reformed by some perfection of virtues turned into affection; which is when a man loveth virtues because they be good in themselves. Many a man hath the virtues of humility, patience and charity to his neighbour, and such other only in his reason and will, and hath no spiritual delight nor love in them, for ofttimes he feeleth grudging heaviness and bitterness for to do them, and yet nevertheless he doth them, but ‘tis only by stirring of reason for dread of God. This man hath these virtues in reason and will, but not the love of them in affection. But when by the grace of Jesus and by ghostly and bodily exercise reason is turned into light and will into love, then hath he virtues in affection; for he hath so well gnawn on the bitter bark or shell of the nut that at length he hath broken it and now feeds on the kernel; that is to say, the virtues which were first heavy for to practise are now turned into a very delight and savour, so that he takes as much pleasure in humility, patience, cleanness, sobriety and charity as in any other delights. Verily till these virtues be turned thus into affection he may well have the second part of Contemplation, but the third, in sooth, shall he not have.