Technical report 270 on Transaction Logic has been substantially revised and updated. The revised report, number 323, is available at this site in ~csri-technical-reports/323/report.ps.gz. This report, numerous other papers, and a prototype implementation are also available at the Transaction Logic web page: http://www.db.toronto.edu:8020/transaction-logic.html These works were made available by bonner@db.toronto.edu. Please send email to this address if you have any comments or questions about these documents, or any difficulties in printing or retrieving them.