Who's who in the environment contains over 300 pages of valuable information on non-commercial organisations who are primarily concerned with environmental issues. Although it's mainly national organisations that are listed, the compilers have also included large organisations based in Manchester. Each organisation has contact details, a concise summary, details of publications and services, and membership information listed.
There's an excellent, comprehensive subject index to help you if you're not sure of the name of an organisation in a particular environmental area. I also had a pleasant surprise when I discovered that all organisations offering skills training, speakers, photographic libraries or funding are listed in a separate section.
To summarise, an excellent reference if you often need to contact a large organisation. Together with CVO's "Greater Manchester Handbook", this book should enable most green groups to find any contacts they need.