"It is important to remember that he reads and writes only green books. That is an important point. I then gave an account of this quality in order to amuse them and win their polite praise."
Relevant extract from Manuscript: Trellis practised another curious habit in relation to his reading. All colours except green he regarded as symbols of evil and he confined his reading to books attired in green covers. Although a man of wide learning and culture, this arbitrary rule caused serious chasms in his erudition. The Bible, for instance, was unknown to him and much of knowledge of the great mysteries of religion and the origin of man was acquired from servants and public-house acquaintances and was on that account imperfect and in some respects ludicrously garbled. It is for this reason that his well-known work, Evidences of Christian Religion, contains the seeds of serious heresy. On being commended by a friend to read a work of merit lately come from the booksellers, he would inquire particularly as to the character of the bindings and on learning that they were not of the green colour would condemn the book (despite his not having perused it), as a work of Satan; this to the great surprise of his friend. For many years he experienced a difficulty in obtaining a sufficiency of books to satisfy his active and inquiring mind, for the green colour was not favoured by the publishers of London, excluding those who issued text-books and treatises on such subjects as fretwork, cookery and parabolics. The publishers of Dublin, however, deemed the colour a fitting one for their many works on the subject of Irish history and antiquities and it is not surprising that Trellis came to be regarded as an authority thereon and was frequently consulted by persons engaged in research, including members of the religious orders, the enclosed class. On one occasion, his love of learning made him the victim of a melancholy circumstance that continued to cause him spiritual anxiety for many years. He acquired a three-volume work on the subject of the Irish monastic foundations at the time of the Invasion and (being in the habit of sleeping during the day), read it throughout the night by the light of his incandescent petrol lamp. One morning he was recalled from his sleep accidentally by inordinate discords from Peter Place, where rough-mannered labourers were unloading hollow tar-barrels. Turning idly to resume the performance of his sleep, he noticed to his great alarm that the three volumes by his bedside were blue. Perceiving that he had been deluded by a subterfuge of Satan, he caused the books to be destroyed and composed a domestic curriculum calculated to warrant the orthodoxy of all books introduced into his house at any future time. Conclusion of the foregoing.
O'Brien, Flann. (1939). At Swim-two-birds. London: MacGibbon & Kee.