Last year, I attended Come Out & Play, a festival of outdoor and alternate reality games, a growing genre of often technologically-enabled games that take place in the real world. The lower Manhattan venues at which this distributed event was hosted were, in some cases, the very same locales where some of the performance art described in C. Carr's "On Edge" took place. Having been in New York at that time, and attended some of the "happenings" she described, I was amazed at how much this innovative new movement has in common, unbeknownst to itself, with this historical but often forgotten moment in intangible art. Indeed, there is one piece Carr describes which is so similar to Blast Theory's "Uncle Roy All Around You" it's uncanny. Anyway, for anyone working on tactical media, street art, or pervasive/locative games, ARG's, etc., this book will provide some valuable insight into contemporary practices through reflection past experimentation.