The letters addressed by Felix Mendelssohn to my father came into my possession in 1870. After Mendelssohn’s death, my father had carefully arranged them in a special manuscript book, and had supplemented them with an index of the contents and a table showing the dates of the principal events in the life of his departed friend. If I have abstained from giving publicity to these letters for so long a time, it is because I thought such delay was in accordance with the wishes of both writers. Many