This document discusses the discovery of Aleister Crowley's lost diary from September 1930, when he traveled to Portugal and met with Fernando Pessoa. Crowley was known to have kept a diary during this period, and portions were quoted by his biographer John Symonds. However, the actual diary pages from September 1930 went missing from Crowley's collected papers. The author was able to obtain a scanned copy of the missing six diary pages, providing a firsthand account of Crowley's movements and activities in Portugal, including his interactions with Pessoa. Analysis of the diary sheds new light on this important historical encounter between the two figures.