During the Nazi occupation of the Netherlands, Anne Frank received a blank diary as a present on 12 June 1942, her 13th birthday.
In the manuscript, her original diaries are written over three extant volumes. It is assumed that the original volume or volumes between December 1942 and December 1943 were lost - presumably after the arrest, when the hiding place was emptied on Nazi instructions. However, this missing period is covered in the version Anne rewrote for preservation. The third existing volume (which was also a school exercise book) contains entries from 17 April to 1 August 1944, when Anne wrote for the last time three days before her arrest.
Anne calls her diary "Kitty", so almost all of the letters are written to Kitty. The manuscript, written on loose sheets of paper, were found strewn on the floor of the hiding place by Miep Gies and Bep Voskuijl after the family's arrest, but before their rooms were ransacked by the Dutch police and the Gestapo. They were kept safe, and given to Otto Frank after the war, with the original notes, when Anne's death was confirmed in the spring of 1945.