What is Philosophy? is the last instalment of a remarkable twenty-year collaboration between the philosopher Gilles Deleuze and the psychoanalyst Felix Guattari. This hugely important text attempts to explain the terms of their collaboration and to define the activity of philosophy in which they have been engaged. A major contribution to contemporary Continental philosophy, it nevertheless remains distinctly challenging for readers faced for the first time with Deleuze and Guattari's unusual and somewhat allusive style. This Reader's Guide offers a concise and accessible introduction to this hugely important and yet challenging work. Written specifically to meet the needs of students coming to Deleuze and Guattari for the first time, the book offers guidance on the philosophical and historical context of the text, its reception and influence, its key themes, notes on reading the text and further reading suggestions.