Dot Zero was a quarterly by Unimark in partnership with Finch Paper that focused on the theory and practice of visual communication. Only five issues were published between 1966 and 1968, and Massimo Vignelli was the designer and creative director of the magazine. Vignelli wanted to make the design exciting, but simple, so he set all type in only two weights of Helvetica and everything printed in black and white.
Michael Bierut interviewed Vignelli about the magazine. Some nice insights on how the publication came about, and its production.
The folks at Rationale Design have made available a hi-res PDF of issue 1 of Dot Zero, and you can see some photos of issue 2 here.