Provided by Carole Bonifas

PCC stands for Prerogative Court of Canterbury and these are wills and
grants of administration.  The PCC was the most senior church court in the
south of England and the wills recorded go back to 1383.  (Before anyone
gets too excited these were mostly the rich and titled until into the 18th
and 19th centuries.) Before 1858 there were hundreds of church courts mostly
under the jurisdiction of the local bishop. But under certain conditions a
will had to be proven by the archbishops court - Canterbury in the south of
England, York in the north.  The conditions was possession of  goods and
cash over £5 in more than one diocese. So for example my ggggrandfather
Dutton Bonifas's will was proven in the Diocese of Wells in Somerset as all
his property was in Somerset when he died in 1849.
The whereabouts of records of wills is v. complicated but is basically:

Before 1858  - local wills - local county records offices
                         PCC wills - the PRO and Family Records Centre
London
After 1858  - local wills - District Probate Registries
                       PCC wills - Somerset House (copies of all wills held
here but I think the fees are steep)

Grants of administration were made (and still are) where someone died
intestate (without a will)

I'm not an expert on this and have only just tried to get to grips with
this.  I know that there are also death duty records which can be searched
as well as the indices and the actual wills. But when you do find one it can
be v. helpful as with Dutton's will which told me which of his children were
still alive on his widow's death 21 years after he died.