John Fiske was not a voluminous correspondent; hence we have not many self-revealing letters to intimate friends and kindred thinkers, regarding his wrestling with some of the great themes which from time to time engaged his mind. The absence of these desirable data is, however, greatly minimized by the possession of his deeply interesting personal letters to his wife and his mother, and of his diaries in which the innermost feelings of his nature are disclosed. These, taken in connection with his published writings, enable us to make out quite a full record of his subjective activities, which, when considered in relation to the seething thought of the time as a stimulating objective environment, yield copious material for a "Life" of Fiske in both its unity and its variety. In the correspondence between Fiske and Spencer, and in the letters of Fiske describing Spencer, we get pleasanter impressions of Spencer's personality than from any other source. To the end, Fiske was thoroughly loyal to Spencer, while immensely broadening his philosophy; at the same time it must be admitted that Spencer withheld the public acknowledgment of indebtedness to Fiske which he so freely admitted privately. This is volume one of a two-volume set.