These letters all concern Rachel Cavendish who wrote them to: her parents the Earl and Countess of Devonshire (later 1st Duke and Duchess); her grandfather; the Earl of Bedford (later 1st Duke); her husband the 2nd Duke of Devonshire, her sister and her son. They span over forty years of her life and begin with childhood letters.
The subject matter includes: the parliamentary decision to make William and Mary King and Queen; her visits to Petworth; fairings presented to her and the Queen by Sir James; her missing the Duke, often complaining of ill humours should he stay apart from her for too long; her planned journeys; a play she sent the Duke; her feelings on her son Sir James being elected a 'parliament man' and Lord Bedford's views on this; hearing music at Paul's Church; picketing; the whereabouts of the Duke and where to send letters; Duke of Ormonde reconciled to court and the willingness of the King to make peace; Lord Exeter leaving town despite the match continuing; the King's visit to Lord Portland; the marriages of Mr Newman to Mrs Trequnil and Lord Stanfort to Mrs Manard; the Duchess of Ormond's infected breast; Lady Roos' "ugly dogs"; and being in the countryside with Mr Charlton.
In the letters addressed to her son James she writes of: his habit of gambling which has lost him much money whilst travelling abroad and concerned Mr Cotteau; an appropriate amount of pocket money allowance for James; the marriage of James's sister Rachel to Mr Morgan; the bad influence of Harry Potter on James abroad and Lady Rachel's wish to bring the servant with him back to England in her service; the death of her mother Lady Russell and for James and Charles but not their servants except Mr Coutteau to consequently go into mourning dress; the danger to James of travelling in France and not staying out on the streets late at night given the many murders that occur; the increasing of James and Charles' allowance on the agreement that James stay away from gambling; changing mourning dress according to the custom of the country they are in; and his return to England. On many of these subjects she writes that she has discussed the matters with James's father before giving their verdict.
Other people and places mentioned in the letters include: Arlington House; Anne Cavendish; Duchess of Somerset; Woburn; Mrs Alington; Sir James; Lady Elan Dona in Holland; Lady Darby; Duke of Shrewsbury; the Earl of Bedford; Lord Chamberlain; Mr Charlton, Lady Roos; Berkley House; Newmarket; Miss Alington and Lord Burleigh; Lord Roos; Lady Brownlow; the Lord Exchequer and his lady; Lord Galway; Lady Winchester.