There are many lines of flight in actuality: the ellipse of a boomerang, the zigzag of a bluebottle, the deadly vector of a bullet. Pynchon's parabola, the trajectory of the rocket, is another such abstract diagram: a meniscus tethered by gravity. The title of Stefan Mattessich's Lines of Flight refers to that famous example, but it also draws attention to his own theoretical trajectory through a philosophy of abstract forms. As a "line of flight" is one of the principal concepts in Deleuze and Guattari's Thousand Plateaus (1980), the allusion should alert us at once to the critical thrust of Mattessich's approach. Mattessich assumes the reader's knowledge of Deleuze and Guattari's post-1968 philosophy, but only as part of a "welter of French theory" (2) with which the book is saturated. Lines of Flight is no undergraduate primer.