It is proposed that the University of California and the California State University and College system cooperate in the development of a compatible machine-readable library patron card or badge that would meet the requirements of campuses in both systems. For discussion purposes, this report suggests the basic features to be included in such a card. As to physical characteristics, the card should be designed to be compatible with a wide variety of available badge reader/transactor equipment. As to contents, the card should include the following machine-readable elements: borrower I. D. number (Social Security number when available), borrower status code, and campus code. A campus coding scheme is suggested. Borrower name, borrower status code, university or college (including campus) name, and validation or expiration date should be human-readable. Signing of the card should be accomplished as part of the card preparation process; inclusion of photograph could be left to local option. The back of the card should carry condition governing its use, as well as campus administrative information. (Author)