"The book contains a large number of illustrative examples along with many diagrams that serve to illustrate the ideas and make the book quite easy to follow. Indeed the diagrams are an essential guide to the geometrical ideas on which the book is based. ... The book can be recommended to both mathematicians and computer scientists as presenting an introduction to an area where further collaboration could be fruitful." (J. P. E. Hodgson, Computing Reviews, computingreviews.com, July, 2016)