Joe Tilson's "Transparency I: Yuri Gagarin 12 April 1961" is a screenprint on perspex created in 1968 that commemorates the Soviet cosmonaut's historic first human spaceflight. The work was published by Marlborough Fine Art in a limited edition of 20 and presented in its original painted wooden frame, exemplifying Tilson's interest in combining Pop Art sensibilities with technological and historical themes. The use of transparent perspex as a support material reflects both the period's fascination with space exploration and modernist investigations into materiality and optical effects.