The best, most accessible introduction to this artist in print - this book is highly recommended for young people who are developing an interest in art. It will nurture their appreciation of art, and open a door to environmentally-informed art history.
The book is organised as a biography, charting the emergence then growth of the main themes, and several key motifs, in Nash's work. The writing is lively, clear and avoids jargon, with discussion focussing on a good selection of glossy illustrations. You can directly check the explanation against the paintings and drawings themselves.
Of course, for a more considered analysis of Nash's ideas, and contextual matters, readers need to look to weighter works such Roger Cardinal's The Landscape Vision of Paul Nash
; but as an introduction, this work is superlative.