One page, on Gads Hill Place stationery, dated 21 May 1868.
The text of this letter reads:
I am deeply gratified by your praises of Harry; and I dearly hope that in his future career he will do us both justice. | Nothing will occur, I trust, to prevent my having the pleasure of giving away the prizes on the day of the Sports. I am sorry to say that my surgeon forms a far less hopeful view of Harry's accident than yours does. | Faithfully yours always | [signed] Charles Dickens
The Rev. Brackenbury was the headmaster of Wimbledon School, which Dickens's 19-year-old son Harry had attended since 1861 and as "Head Censor" was nearing the end of his final year, before going up that fall to Trinity Hall, Cambridge (the only Dickens child to attend university). Henry Fielding Dickens was the eighth of Dickens's ten children -- named of course for one of Dickens's favorite authors, Henry Fielding; it is said that CD wanted to name him for another author, Oliver Goldsmith, but worried that his son would be teased at school as "Oliver asking for more."
Earlier that same month, Dickens had returned from his "exhausting" five-month tour of North America. Although Dickens here tells Brackenbury that nothing should prevent him from giving away the Sports prizes (on May 30th), the Wimbledon prizes would in fact be handed out by someone else, "in the unavoidable absence" of Charles Dickens; his sister-in-law Georgina Hogarth and his eldest daughter "Mamie" Dickens attended in his absence.
As for "Harry's accident" referred to in the letter, Dickens wrote about it the very next day in a letter to J.C. Parkinson:
My boy is laid up at Wimbledon (he is headboy there now and going up to Cambridge) with a lamed knee. Having lamed it two years ago, he was medically admonished not to jump -- of course therefore did jump -- and probably will never jump again.
Dickens's "hope that in [Harry's] future career he will do us both justice" did come to fruition: Harry is generally considered to have been the most successful of the Dickens children, becoming barrister Sir Henry Fielding Dickens K.C. Harry died in December 1933 when, as was his custom, he crossed a busy London street by raising his walking-stick rather than by looking both ways -- and was run over by a motorcycle. (He was the last surviving Dickens child, which is why Dickens's last book, THE LIFE OF OUR LORD, though written in 1846, was not published until early 1934 -- as Dickens had stipulated that it not be published until all his children had died.)
One final unrelated tidbit: on the very day after Dickens wrote this letter, the last public hanging in Britain took place (as the Capital Punishment Amendment Act took effect on the 29th); for decades (but especially as revealed in his 1849 letters to The [London] Times), Dickens had campaigned against public hangings -- not against the hangings themselves, but against the public spectacles they had become. This letter, documented in The Letters of Charles Dickens, Vol 12 page 115, is in fine condition (original fold-marks from mailing). Item #14661