During the last decade of Peter Cooper's life, the writer of this biographical sketch enjoyed some degree of intimacy with him, as professional adviser and traveling companion, and also, incidentally, as consulting engineer of the firm of Cooper and Hewitt, and manager of a department in the Cooper Union. This circumstance, together with the preference kindly expressed by Mr. Cooper's family, doubtless influenced the selection of the writer for the honorable task of preparing this book, -a task which was welcome as a labor of love, though the execution of it has been hindered and impaired by the demands of other duties. The real difficulty has been to compress within the prescribed limits a story covering so many years and so many topics, yet not possessing those features of dramatic action or adventure which could be treated briefly, with picturesque effect. Mr. Cooper's family has kindly furnished abundant material for this work, including, besides his own published utterances, the notes of the stenographer to whom Mr. Cooper, in the last years of his life, dictated his "reminiscences." The use which has been made of these will be evident to the reader. Beyond an occasional revelation of the character of the speaker, or a side-light thrown upon the manners and conditions of our early national life, they have not furnished valuable data; and the study of them suggests an observation which may be heeded with advantage in similar cases hereafter, though it comes too late to be useful in this instance, namely, that the recollections of old people with retentive memories, like Peter Cooper, may be invaluable, if they are intelligently aroused and guided; but if the speakers (as in his case) are left to their own initiative, they are too likely to furnish superfluous accounts of events already described more accurately in authentic contemporaneous records.