This book is the very first monograph of one of the largest collections of avant-garde art in Europe – the Archive of Franciszka Themerson and Stefan Themerson. Honorata Sroka poses a fundamental research question to the materials being analysed: how are avant-garde ideas realised in the archive? Nevertheless, the titular collection does not limit the scope of the issues addressed in this publication, as the adjective ‘avant-garde’ is linked to the proposal of a new theoretical perspective related to the collections of artists. By presenting the case of the Themersons against the backdrop of several other institutions – which were vanguard in the sense that they employed experimental ideas in their organisational methods (museums, galleries, schools) – Sroka develops the theory of the ‘avant-garde archive’ as a tool for analysing collections that break away from the traditional paradigm of preserving traces of the past.