The Source Book offers a parallel space of reflection occasioned by the exhibition of Geoffrey Farmer at Witte de With. Three extraordinary essayists – Diedrich Diederichsen, Vanessa Desclaux and Thierry Davila – were invited to encounter the artist’s mercurial practice in different contexts. They speculate on his inventive approach to temporality, to the spaces of theatre, film and performance and to the workings of memory, meaning and art historical reference. As a further resource to his imaginary method, Farmer himself recomposes visual and textual fragments of his exhibition, which after one-month of daily transformation, came to be known as Forgetting Air.