Finding Moonshine by Marcus Du Sautoy
Another book on symmetry, leading into group theory and progressing up to groups like the Monster. That side of the material is also covered by books such as Symmetry and the Monster. The really interesting part of the material was the autobiographical details about the author and his journey towards group theory. This material covers meetings with some of the interesting characters of the field such as John H. Conway, with short interesting stories about them.