[1] Berry became notable through her association with close friend Horace Walpole, whose literary collection she, along with her sister and father, inherited.

As the older son of Ferguson's sister, he began working at his uncle's counting-house in Broad Street, Austin Friars.

Their religious instruction consisted of Mary reading aloud a Psalm to her grandmother every morning, and one of the Saturday papers from the Spectator every Sunday.

A letter he wrote in October 1788 related how: “he had just then willingly yielded himself up to their witcheries on meeting them at the house of his friend Lady Herries, wife of the banker in St. James's Street”.

He established the sisters at Teddington in 1789, and two years later, in 1791, he prevailed upon them to move into Little Strawberry Hill, a house previously known as Cliveden, the abode of his friend Kitty Clive, the famous actress.

"There is a tradition handed down by Lord Lansdowne", says the Edinburgh Review, "that he (Walpole) was ready to go through the formal ceremony of marriage with either sister, to make sure of their society and confer rank and fortune on the family - he had the power of charging the Orford estate with a jointure of £2,000 a year.”[3] This did not occur.

In 1779, Mary's hand had been sought in marriage by a Mr Bowman and she wrote long afterwards that she had "suffered as people do" at sixteen "from what, wisely disapproved of, I resisted and dropped.

He also bequeathed to Robert, Mary, and Agnes Berry his printed works and a box containing manuscripts, to be published at their discretion.

[3] Other works she published include Walpole’s the Mysterious Mother and another of her own plays, a farce called The Martins, set down in a manuscript list of her writings, which was never produced either in print or on the stage.

[3] Berry published the first volume of her most famous work, A Comparative View of the Social Life of England and France from the Restoration of Charles the Second to the French Revolution, in 1828; the second volume, Social Life in England and France from the French Revolution in 1789 to that of July 1830, appeared in March 1831.

It was reissued as a collected whole in the complete edition of her Works in 1844, with a new title, England and France: a comparative View of the Social Condition of both Countries alongside Fashionable Friends and her other writings.