Philip "Flip" Slier (4 December 1923 – 9 April 1943) was a Dutch typesetter of Jewish origin who lived in Amsterdam during the German occupation of the Netherlands in World War II. At the age of 18, he received a letter from the Jewish Council of Amsterdam — under orders from the German occupiers — that he was to report to Camp Molengoot or face arrest. He wrote 86 letters from 25 April to 14 September 1942 detailing his experiences as a forced labourer at the labour camp. Eventually he escaped to Amsterdam and lived as an onderduiker (a person in hiding); he frequently disguised himself and moved to different hiding locations to evade detection.