Here is a book that teaches how to concentrate along common-sense, practical, and scientific lines. "The Master Key" by Dr. L. W. de Laurence teaches Scientific Concentration through a course on Mind-Training. When it was written in 1914, the book was part of a lively increase of the spirit of research and study in psychology, concentration and mental discipline. Scientific Concentration and Mind-Training aim at the unfolding of one's individuality to the fullest to become well-balanced men and women.