Titles of forthcoming reviews will be published in each issue to stimulate authors to submit manuscripts reporting original research on related topics. If these are received before the deadline, and accepted, these papers will have priority. The deadlines for submission are: 40.1, June 1990,40.2, September 1990,40.3, December 1990,40.4 March 1991,41.1, June 1991, and 41.2, September 1991.