Internationale Situationniste
The first issue was published in June 1958.
From libcom.org:
The Situationist International (SI) produced the journal Internationale Situationniste between 1958 and 1969. It functioned as the movement’s main organ, and over 12 issues its pages documented the evolution of Situationist theory, the members’ thoughts on everyday life, and the internal/external dramas of the group.
The booklets measure 235×155 mm and come in metallic covers of changing colors. The typography is always the same, with the journal’s name shown in lowercase letters from the regular style of Charactères Simples.
A collection of all twelve issues was also compiled into a slipcase made by Julie Nadot.
The covers of all twelve issues with a supplement to no. 10, Adresse aux révolutionnaires de tous les pays, in French, Spanish, German, English and Arabic.
