By the method, the book that I pointed out in the video is That Wild Country by Mark Kenyon..

Googles.
Ngram Viewer is a search tool that students can use to explore the use of words and names in books released in between 1800 and 2019. The Ngram Viewer shows users a graph showing the first appearance of a word or name in literature and the frequency with which that word or name appears in literature since 1800. The chart is based on the books and periodicals that are indexed in Google Books.

The Ngram Viewer will let you compare making use of several words or names in one chart. The example that I offer in this video is to compare the usage of the terms “National Parks,” “National Forests,” and “National Forest Service.” By taking a look at the Ngram Viewer for those terms I can see that they begin to appear more regularly around 1890, have a lull in the 1940s and 1950s, and then appear more frequently again in the 1960s..
Ngram Viewer is based on books indexed in Google Books. That is why listed below every chart produced by Ngram Viewer you will discover a list of books about each of your search terms. Those books are organized by date..
A 3rd part of Ngram Viewer to keep in mind is that it deals with multiple languages including English, French, Chinese, German, Italian, Russian, Hebrew, and Spanish..

Applications for Education.
As I pointed out in the video above, the Ngram Viewer can offer an excellent way to start a research activity for trainees. Have them get in a few words then analyze the chart to recognize peaks and valleys in the frequency of the words use. Ask them to attempt to identify what would have caused those words to be utilized more or less often at various periods in history.

Ngram Viewer is a search tool that trainees can use to check out the usage of words and names in books published in between 1800 and 2019. The Ngram Viewer reveals users a chart illustrating the first look of a word or name in literature and the frequency with which that word or name appears in literature given that 1800. The Ngram Viewer will let you compare the usage of multiple words or names in one graph.