Legal history: England & common law tradition: Local legal officials

Anglo Saxon predecessor
‘Scir-gerefa’ or Shire Reeve & system of tithings and hundred courts (local criminal courts)

Norman development

Sheriff (combination Shire Reeve + Vice-comte)

Frankpledge - 
Sheriff's tourns (local criminal courts)

The need to keep the King's Peace, punish criminality, and raise revenue for the crown

Top level subject searches in SOLO

NOTES 

1. Don't limit your subject search strings t o those with England in them.  Great Britain is the default term for the landmass of the British Isles in search terms. So  Justices of the peace -- Great Britain may well include works  on the JPs pre 1707 as well as after 1801. 
2. Try subject searches both with and without history in the string! eg Coroners England History  This may be too fine a filter. So try  again without History

Justice, Administration of  
Criminal Justice, Administration of  
Local government 
Counties -- England -- History;
England -- Administrative and political divisions -- History
Parishes (local government)
Peace officers
Sheriffs
Justices of the peace
Coroners
Constables  
Churchwardens

Evolution of office since 1066
Keepers of the Peace 1195

Guardians of the Peace 1327

Justices of the Peace 1361

Lay Magistrates synonym JPs

1813 First paid professional JP

1835 Municipal Corporations Act empowered borough to apply for the provision of a paid or "stipendiary" magistrate

1919 first woman JP Councillor Ada Summers (when also the Mayor of Stalybridge)

Coroners

Records of Coroners' Inquests (held in cases of sudden unexplained deaths or possible cases of suicide) are a very useful source for social and economic historians. It is worth searching SOLO for Death -- Causes -- History -- Sources - as many have been at least calendared.