In many cultures lines take centre stage in art and science, in writing, drawing and construction. This publication explores the fascination and power of the phenomenon of the line from the point of view of various academic disciplines ranging from the history of art to philosophy and the history of science. There are no lines in nature; lines are always the expression of human actions, perception and design. Lines divide or connect; they are sometimes static and sometimes gestural and full of movement; they represent and create forms in space and time. The essays in this volume elucidate the semantic and conceptual depth of the line in European, Asian and Islamic cultures and reveal the continuity and transformation of the line over the course of centuries as a constitutive element in architecture, art and writing and as a medium of expression in choreography and scientific and technological fields.