The fruit of a lengthy research, this book shows for the first time a significant selection of René Heyvaert's mail art. The latter is linked to the Belgian artist’s multiform oeuvre—which retains, given that René Heyvaert (1928–1984) was originally an architect, an overt material and spatial relation to its environment—as well as to his personal life: his gradually deteriorating health, and the loneliness that fed his epistolary vocation.