Cover: A rigid, cycloaliphatic polymer, poly(6,7-bicy-clo[3.2.0]heptylene), was synthesised via the olefin addi-tion polymerisation of the cyclobutene derivative,bicyclo[3.2.0]hept-6-ene. Early and late transition metalcatalysts were used for these polymerisations. The covergraphic also shows the preferred conformation of themonomer. Further details can be found in the article byK. Curran,* W. Risse,* L. Boggioni, I. Tritto on page 707 LarryDalton is acknowledged for the design of the cover picture.