The species descriptions follow the most recent botanical classification (Farjon, 2010) and cultivar information has been compiled with reference to the RHS International Conifer Register and Checklist, including as yet unpublished data. There is a unique appendix listing all the principle conifer collectors, nurseries, arboreta and individuals responsible for introducing new cultivars over the last three centuries.
The encyclopedia continues the fine tradition of conifer cultivar reference works started by Murray Hornibrook in 1923 and added to every 20–30 years by subsequent conifer specialists. The high quality photography shows the general appearance of the plants, and in many cases details special features. Many were photographed in summer and winter to show colour and texture changes through the seasons