Since the early days of the graffiti movement in late 1970s New York, street art has transformed cities around the world. Today it is a hugely popular, yet still highly controversial art form. In Abstract Graffiti, Cedar Lewisohn provides a vibrant account of the outer limits of street art and graffiti that are being explored by artists in cities as diverse as London, Prague, Philadelphia and São Paulo. The work of these artists is abstract not necessarily in the sense that it is non-figurative; rather, it may embrace a fresh, abstract approach to art. Lewisohn interviews both established graffiti artists and new practitioners of avant-garde forms of art in public spaces - such as Knit Graffiti and Street Training - and traces the art-historical lineage of these abstract trends. Addressing such issues as street art as a form of protest, graffiti as a crime, the place of street art in museums, and the evolution of materials, this book offers unrivalled insight into some of the most exciting and challenging work on the contemporary art scene.