This book contains the latest developments of the theory of discontinuous groups acting on homogenous spaces, from basic concepts to a comprehensive exposition. It develops the newest approaches and methods in the deformation theory of topological modules and unitary representations and focuses on the geometry of discontinuous groups of solvable Lie groups and their compact extensions. It also presents proofs of recent results, computes fundamental examples, and serves as an introduction and reference for students and experienced researchers in Lie theory, discontinuous groups, and deformation (and moduli) spaces.

Unlike some other reproductions of classic texts (1) We have not used OCR(Optical Character Recognition), as this leads to bad quality books with introduced typos. (2) In books where there are images such as portraits, maps, sketches etc We have endeavoured to keep the quality of these images, so they represent accurately the original artefact. Although occasionally there may be certain imperfections with these old texts, we feel they deserve to be made available for future generations to enjoy.

Unlike some other reproductions of classic texts (1) We have not used OCR(Optical Character Recognition), as this leads to bad quality books with introduced typos. (2) In books where there are images such as portraits, maps, sketches etc We have endeavoured to keep the quality of these images, so they represent accurately the original artefact. Although occasionally there may be certain imperfections with these old texts, we feel they deserve to be made available for future generations to enjoy.

Please note that this Floris Books edition has been revised for UK and European notation, language and metric systems. From the early peoples who marvelled at the geometry of nature -- the beehive and bird's nest -- to ancient civilisations who questioned beautiful geometric forms and asked 'why?', the story of geometry spans thousands of years. Using only three simple tools -- the string, the straight-edge and the shadow -- human beings revealed the basic principles and constructions of elementary geometry. Weaving history and legend, this fascinating book reconstructs the discoveries of mathematics's most famous figures. Through illustrations and diagrams, readers are able to follow the reasoning that lead to an ingenious proof of the Pythagorean theorem, an appreciation of the significance of the Golden Mean in art and architecture, or the construction of the five regular solids. This insightful and engaging book makes geometry accessible to everyone. Readers will be fascinated with how the knowledge and wisdom of so many cultures helped shape our civilisation today. String, Straight-edge and Shadow is also a useful and inspiring book for those teaching geometry in Steiner-Waldorf classrooms.