Umbrella is a quarterly art journal that covers artists' books, mail art, and other multiple editions including audio and video works. They published a print version from 1978 to 2005 and then moved online. Indiana University-Perdue University Indianapolis' Library now has a searchable archive of all their back issues. Go poke around and see reviews of all sorts of old books and magazines, interviews with artists, thoughts on anything from computer cataloging of images to performance art collaborations, and notes from parties and events. You can also subscribe to Umbrella online at their site.