The following sites may be of interest to those researching the Hagg*r name:
www.hagger.org A site owned and managed by Martin Hagger, one of the main contributors to the study. The site shows the ancestry of numerous Haggers, but mainly those who originated in Therfield, Hertfordshire.
www.therfield.net A sister site to hagger.org again owned by Martin, and full of data on Therfield, including indexed census extracts.
A forum for the discussion and sharing of information regarding the Hagger surname and variations.
The Langley of Essex home page you will see a number of Hagger’s there, see William Hagger.