Interesting "vintage" book published in 1970, Knots was written by R.D. Laing, the Scottish psychoananalyst who came to be identified with the "anti-pschiatry" movement because of his view that mental illness could be understood as a potentially transformative experience not unlike a shamanic journey. He also linked the development of psychosis with family relations--a view that has been more-or-less left behind the the wake of psychopharmacology.
A series of word/mind games that are fun to decipher. Back cover: '"In his earlier work, Laing guided the reader to understanding. In 'Knots', he compels him to experience... To grasp this dense and difficult book, one must be willing to follow Laing in his spirals of descent. If 'Knots' is to yield, one must yield to the knots."' - James S. Gordon, 'The New York Times Book Review'.
It's not difficult as in physics or "Paradise Lost". It's more like Raymond Smullyan.