What is the author's tone in the biography, Thoreau of Walden Pond?

The author takes an avuncular tone in the book, which means he speaks like a friendly nurturing way like a favorite uncle might speak to his nieces and nephews. The tone is warm, gentle and full of admiration for Thoreau. Occasionally, he uses humor to make a point. The only time this positive tone changes is when North attempts to excite young readers with adventure tales. Because the book is dated, these may seem insensitive, especially when he's talking about murdering Native Americans.