1st letter:  17 Sept 1888
2nd letter: 24 Sept 1888
"Dear Boss" letter:
"Saucy Jack" postcard:
"From Hell" letter
Openshaw letter
Police theory on author

 The "Ripper letters" is the term given to the correspondence, purporting to be from the murderer, received by the press, police, and individuals, during the time of the murders. The official files contain over 200 letters.
 The first two letters were not made public.
 The "Dear Boss" letter and "Saucy Jack" postcard, signed "Jack the Ripper", were reproduced in newspapers and on placards outside police stations.
 The "From Hell" letter and piece of kidney were sent to George Lusk, chair of the Whitechapel Vigilance Committee. Dr Openshaw, who examined the kidney, received a letter, purporting to be from the murderer.
  Later, police officials gave their theory on author of "Dear Boss" letter.

                                                           FIRST LETTER: 17 September 1888