The ordinary man reads many books, and each one leaves some impression and has some influence upon his later thoughts, though in time the recollection, not only of the contents of the book, but even of having read it, may fade away. This is the explanation of some cases of literary plagiarism: a previously read phrase comes up from the unconscious, and all recognisable connections with memory having been lost it is greeted as a fresh creation and given rank accordingly. There is still another type of forgetting: most of us know the man who 'draws the long bow', who embellishes his story and embroiders it with imagined incidents, whilst we listen and wonder how much the narrator himself believes. Fishermen's stories and snake yarns are examples, and one explains the mental process of the story-teller by saying, 'He's told the story so often that at last he believes it himself.' The process is really one of forgetting and is closely allied to the repression of an unpleasant memory, for the man is the victim of a mental conflict: on the one side is his desire to tell a good story, and on the other is his moral complex which forbids a lie, so he solves the conflict by forgetting that the embroideries are inventions. This type is an important one, and what I shall call the 'repression of the knowledge of deceit' plays an important part in the explanation of the abnormal phenomena with which this book deals. In tracing the development of the abnormal we must start with what is nearest the normal, and the man who embroiders his story gives an illustration of the simplest form of this particular repression. Now, just as memories are repressed because they were repugnant to the other contents of the consciousness, so other complexes may be repugnant and meet the same fate. To be torn by conflicting emotions is the fate of most people at some time or other, and the conflict between two complexes may be solved in various ways. The healthy way is to face the difficulty, to reason it out, and reach a conclusion by which action may be guided; another way, a common one, is to seclude one complex in a logic-tight compartment and so avoid the conflict. The man who uses sharp or shady methods in the city and is a gentle-minded philanthropist in other walks of life is using the latter method, and will produce such rationalisations as 'business is business' when the contents of his different compartments need protection from each other.