This is a tree book unlike any other. While trees have long been celebrated, their widespread admiration usually produces those field guides we all know, describing habitat, form, leaf and bark, meant to be carried with us as we wander the fields and woods, or, more rarely, those handsome books dedicated to arboreal beauty and character, such as those of Thomas Pakenham filled with fine photographs of extraordinary specimens. Absent from the literature of trees, however, is a survey of those that have been created by and exist only in the human imagination. These are the truly remarkable ones, including one that is the source of life, another the source of the knowledge of good and evil; some that have a human ancestry, others human characteristics; one that is soundless, another that speaks of the future, and still another that encompasses the entire world. That we cannot touch their bark, clasp their trunks or see their foliage and fruit only addes to their appeal, for they exist only in our minds.Gathered here are some of these extraordinary artifacts of the imagination produced, during man's long journey from the far past to the present, on the real trees that have sheltered and nourished us, physically and intellectually, enabled us to cross the oceans and both warmed and inspired us. That a mystical, atabistic bond exists between us and these aristocrats of the vegetable kingdom is evidenced whenever we stroll under a redwood or yew or enter a forest.This is a field in which you know more than you think you do. The Tree of Life and the Tree of Knowledge of Good and Evil are obvious examples. Mythology provides us with Yggdrasil, the Norse world tree and the arboreal metamorphoses described by Ovid. Other specimens have roots in literature, philosophy, history, and folklore, and, as befits a new guide to imaginary beings, there are several that have only just been discovered.