The spread of Christianity in Japan, which later was to cause so much trouble and anxiety among the ruling classes, began with the arrival of St. Francis Xavier in 1549. In his footsteps there followed large numbers of missionaries, the majority of them members of the Society of Jesus, of which Xavier himself had been one of the founder members. One of their duties was to provide a periodical account of the progress of their missionary activities, and the letters which they wrote to Europe were read avidly by their fellow Jesuits and by the laity alike.
　　The present volume is the first collection of these letters to be published, and includes examples from the years 1551-1566, beginning with one written by St. Francis Xavier from Goa before his departure for Japan, and including his first letter from Japan, that dated 5th November 1549 in Kagoshima. The volume contains a total of 82 letters, and is also remarkable as offering one of the earliest printed specimens of Japanese writing to be seen in Europe.