Harrison explains that he is writing a "a physic history from which empirical history derives its inspiration." It is a history of the place of forests in the western psyche. For example, Harrison writes, "But why should forests haunt the mind like some mystical dream or nightmare that every now and then spreads its long, prehisotrical shadows over the ordinary clarity of things modern? On the basis of what "data of prehistory,"...does the forest become dense with associations and monstrous fears?"

His meta narrative is as follows: "Civilization define[s] itself at the outset over and against the forests." There has always been an antagonism between human culture centers and forests. Forests are a huge part of today's cultural memory.

His method is to scan works of culture, namely literature, for expressions of an attitude towards forests. His "ages" include your basic Greeks, Romans, medieval, Renaissance/humanism, Enlightenment, Romanticism, Modernity.

Criticisms: Frequently looks at a bit of literature and concludes "forests were..." or "forests were becoming..." Harrison doesn't make explicit to whom they were "becoming..." That is, he is not too critical about the authors of his sources or the nature of their audiences. Did the limited reading audiences cut down the trees? If not, what were the concrete mechanisms of deforestation? He writes, here is the attitude, then, here is the scope of deforestation, there's no connection in between.
Harrison also has little respect for chronology; for example, Moses becomes an example of the medieval mindset.

I was assigned portions of "Forests" for a research writing class. The writing is just beautiful; the work as a whole is nearly overwhelming. The discussion on Walden in the fifth chapter is not to be missed. Overall an incredible example of literary criticism, almost out of place among current literature, but much welcomed and thoroughly appreciated.

My old Cambridge tutor said that the only works of modern literary criticism he'd sell his shirt for were *Seven Types of Ambiguity* and *The Wheel of Fire*. For a long time I agreed. Then I read *Forests*. It is quite simply the most profound, the most moving, the best-written, the most important work of literary criticism of the late twentieth century.