  In this thesis I present measurements of the physical properties of the
nuclei of Jupiter Family comets (JFCs), based on time-series observations. From
the time-series photometry rotation rates and elongations were measured, and
from these constraints were placed on the bulk density and porosity of nuclei.
Multi-filter imaging was performed to enable measurement of their surface
colours. In addition, a large amount of `snap-shot' imaging was performed
during the observing runs, and taken with the time-series data is used to
measure nuclei sizes. These results are compared with other data from the
literature to study the general properties of JFC nuclei.
  (Abridged)
