sentences:  Ralph Waldo Emerson had recommended Etzler's book to Thoreau and suggested that he write the review.Emerson himself had been impressed enough by Etzler's technological prescience to worry about whether the vast energy and machinery of the future would make the working class obsolete and endangered.As Thoreau sees it (once he gets the review behind him and starts letting his own philosophy take center stage) the problem is not that we have not applied sufficient energy and technology to put our great schemes into action, but that we have not energetically applied ourselves to improve our schemes.