Neil Gunn, one of Scotland's most distinguished 20th century novelists, wrote his first book in 1926 and his last 30 years later. Although certain themes remained central to his writing, the author's emphases and interests changed with the passage of time. In other words, the development of his vision followed several paths and reflected the influence of a succession of external events that encompassed the Recession and political crises of the 1930s, the Second World War and the beginning of what came to be known as the Cold War. Throughout Gunn's long writing career, which could be described as a spiritual odyssey, the quest for freedom, happiness and completeness was always there.

By the time he came to write The Silver Bough in 1948, he had established himself as a novelist of considerable standing. His Morning Tide (1930) was a Book Society choice and his Highland River (1937) the winner of the prestigious James Tait Memorial Prize. Notable among his other books were three epic recreations of Highland history, Sun Circle (1933) covering the genesis of Caithness, Butcher's Broom (1934) the 'Clearances' and the immensely successful The Silver Darlings (1941) the herring boom of the early 19th century. The Green Isle of the Great Deep (1944), which preceded George Orwell's 1984, illustrated the indestructible strength at the heart of a Highland community and its old and youthful representatives in the face of the deadening threat of totalitarianism. This ambitious novel was read with great interest by the famous Swiss psychiatrist, Carl Jung.

The Silver Bough represents a new development in Gunn's writing, a development that can be explained, at least in part, by the events leading up to the end of the Second World War. The dropping of the atomic bomb on Hiroshima had shown the ugly side of nuclear physics and dampened hopes for the development of nuclear science for peaceful ends alone. Gunn, who had a strong mathematical bent, was fascinated by nuclear physics, but was saddened by the threat to mankind of nuclear weapons of mass destruction. Paradoxically, he saw a value in mapping out a future for humanity through looking back to ancient times and beyond for perspective and meaning. In his childhood he had been familiar with the brochs and cairns of his native Caithness; as a mature writer he had been fascinated by standing stones near his home in the hills near Dingwall in Ross and Cromarty. Archaeological sites and speculation about them had appeared in several of his books. He understood the value of archaeology.

At the heart of The Silver Bough is a hilltop cairn surrounded by standing stones. Its excavation is the task of Grant, a middle-aged archaeologist, who is the principal protagonist in the novel. The excavation dominates the story but as important is Grant's relationship to the local community. Among its members are his crofting landlady arid her beautiful granddaughter, Anna, and her fatherless child, Sheena, the local laird, Martin, and the mentally retarded Andy, whom Grant employs as his manual labourer. Each has a part to play in the mosaic of seemingly unrelated events, and each in a curious way contributes to Grant's speculations on how the Neolithic people of the cairn lived their lives.

The simple charm of the life led by the crofting family and the quiet tenor of Highland life have a timeless quality about them, which links the present with the past and provides a meaningful influence on Grant's musings. One of his epiphanies is described in this way. 'The wind flattened and combed the irrepressible grass, and the rain was a driving mist against the dark-brown mountains. All at once he (Grant) saw old Fachie by the sheltered gable of his house, his left arm outstretched and his dog rushing low to the earth to round up a cow or stirk that had gone into the young corn. There were no other figures to be seen and in a moment the little drama with the old bent figure might have been of any age back to Neolithic times.'

Andy too connects present with past, although unwittingly. His shambling gait and inability to express himself other than by gesticulations and grunts feed Grant's imaginative mind with thoughts of the original community of the cairn.

As imaginative as Grant's ideas is the plot of the book, which is as intricate as a Celtic ornamental design. To the mysteries of the skeletons of a mother and child found in the cist in the cairn is added the question of the identity of the father of Anna's child, Sheena. Embroidered in the theme of deserted mother and child is the myth of the Silver Bough, a story lovingly told to the little girl by her great grandmother. It concerns a king who, in his desire to acquire the magic bough and its silver bells - and thereby happiness - sells his wife and daughter to the King of the Sea.

A second mystery develops round the discovery and loss of a crock of gold from the cairn. After the find, the crock is seized and hidden by Andy. Efforts to induce Andy to divulge the hiding place meet with no success and the search is on – a search that will end when a standing stone unexpectedly claims a 'sacrificial' victim.

Both strands of the plot bring into vigorous play the main characters in the story. Grant's musings and speculations spread outwards like ripples in a loch and affect the lives of those he meets. In particular, they give some meaning to the life of Martin, who is mentally and emotionally scarred by his experiences in the war. The more Grant applies himself to the unsolved mysteries of the skeletons and the gold, the more he embarks on a process of self-discovery.

Although the mythical theme running through the book is serious, the incidents and conversations surrounding the main action of the story are laced with humour. Particularly amusing are the conversations with fellow archaeologists in deviously learned talk. Even nature imitates the humour of the intellectuals. 'The green of the grass was greener, fresher, as wind and rain swept under the hurrying sky. The grasses flattened themselves, wiggled in green mirth that held on. The rowan tree was a more solemn riot, full of convolutions of itself and high bursts of abandon, but sticking to its own root at all the odds. For a miraculous moment the cat appeared on the garden wall. A blackbird whistled and was gone. Between the bursts he heard the pounding thunder of the sea.'

The legend of the Silver Bough and the quest in Celtic mythology for the crock of gold are vital ingredients in Gunn's belief in the importance of understanding the past and preserving the continuity of life from antiquity to the present - a continuity that can only be maintained if the wisdom of the past is neither forgotten nor forsaken. For him the preservation process is sustained more by myth and living tradition than by the written word in scholarly books. A sentence from the preface of The Golden Bough by the famous anthropologist James Frazer sums up Gunn's views on the value of living tradition most accurately. 'Compared to the evidence afforded by living traditions, the testimony of ancient books on the subject of early religion is worth very little'. To that, Grant of The Silver Bough adds, 'And not only of early religion.'