She started Письмо it in 1990 and finished the manuscript in 1995 (all done on an old manual typewriter). It then took over a год to even find a publisher that would accept it, before a small number of copies were finally printed and distributed in 1997.
Was watching a great documentary on her recently -
link the terrible mental and financial state she was in when she started Письмо Philsopher's Stone, and then later
link to the flat in which she wrote it (and sees the HP Книги on some Болталка kid's shelf lol)