This is one of the Gunn novels which can be enjoyed on two levels. On one level, it is written in the picaresque style, telling how the hero travels from place to place, meeting separate groups of characters and having self-contained adventures; it is held together by the dominating quest of the hero.
It tells of a long circular walk undertaken by Peter Munro, a Professor of History, among the moors and mountains of the Scottish Highlands, and of the varied characters he meets along the way, from a hospitable old widow to a trio of illicit whisky distillers and a group of fishermen, and on that level, the episode of the fishermen striving to reach harbour is the highlight.
It is a journey in two senses, however, for the real theme is the progress that Peter makes towards the discovery of metaphysical or spiritual truth: what human life is really all about. It has nothing to do with lost youth.
Water is the symbol of life, both physical and spiritual; the well or spring of the title is featured in various folk tales and myths, including a long story by Wiliam Morris, and is present at the beginning and end of Peter's quest. The reader is taken, by way of optical illusions and a haunted house, on a journey signposted by special moments in which the traveller senses a "something" which is beyond commonly-perceived reality, the kind of experience which T.S.Eliot explored in "Four Quartets". Here in Gunn's novel, it is symbolized by an extraordinarily beautiful wild rose which is tantalisingly beyond reach.
The essence of the truth which Peter discovers is that transcendant reality is reached through self-abandonment to the present experience or relationship; the key to eternal fulfilment is in unconditional love.