Philip Mechanicus worked for the social-democratic daily Het Volk after completing primary school. He started at the shipping and records department and studied on his own to become a journalist. Following his military service he worked for the Sumatra Post in Medan and subsequently for De Locomotief in Semarang.
In 1919 Mechanicus returned to the Netherlands. In August 1920 he joined the foreign affairs editorial staff of the Algemeen Handelsblad. He wrote travel reports about the Soviet Union (1929-1934), which were published in the volume 'Van Sikkel en Hamer,' and about Palestine (1933): 'Een Volk bouwt zijn Huis.'
Philip Mechanicus was forced to resign from the newspaper staff immediately after the Nazis invaded and briefly wrote under an alias. On 27 September 1942 he was arrested in the rear compartment of a tram in Amsterdam. He was not wearing a star. He was taken to the camp at Amersfoort via the house of detention on the Amstelveenseweg and was tortured there. On 7 November 1942 he was transferred to Camp Westerbork, where he was admitted to the infirmary.
Philip Mechanicus kept a diary at Westerbork from 28 May 1943 through 28 February 1944. After the war the diary was published in the book 'In dépôt'.
On 8 March 1944 Philip Mechanicus was deported to Bergen-Belsen, from where he was sent to Auschwitz-Birkenau as part of a transport of one hundred and twenty convicts on 9 October 1944. All were executed upon arrival.
Ph. Mechanicus, In dépôt. Dagboek uit Westerbork (Amsterdam 1964) 11, 81, 200 en achterflap