«The act of adding artistic contribution to the delivered work and passing it on. There are a variety of styles. Some may develop into an open ended chain in which a work sent by an artist from another country is modified by the recipient who then passes the modified work on to another artist, and the act goes on and on eternally.
Some prefer communication through exchanging their work on a one-to-one basis. An artist sends a blank book to the other artist to fill in one of the blank pages with their artistic intervention, then they pass the book to another artist for the act to be repeated until the entire book is filled in becoming a collection of artworks». *
This process was the basis of the communication Ray Johnson started to widen his network. He cut his collages in pieces and asked the recipient to add and return. After the originals came the photocopies and they became a widespread tool to spread add & pass / add & return works in the mail-art network.
* (Eiichi Matsuhashi, Book for Mail Art, Karuizawa, Karuizawa New Art Museum, 2018)