The critic or biographer, who writes from materials already before the public, may be excused if he give way to his prepossessions and partialities, and limit his task to the representation of all that justifies and supports them. If he have any misgivings, that, in following the direction of his prepossessions, he may not have taken the straight line of truth, he may be assured, that if the cause be one of any interest, an advocate, having the same resources at his command, will speedily appear on the other side. But when original manuscripts are for the first time to be used, it is due to truth, and to the desire of mankind to satisfy themselves about the real characters of great men, that they should be so presented as to afford the means of impartially estimating those to whom they relate. We possess many brilliant Eulogiums of the leaders of our race--many vivid pictures of their virtues and their vices--their greatness or their weakness. But if a humbler, it is perhaps a no less useful task, to represent these men--their character, their conduct, and the circumstances of their life, precisely as they were; rejecting nothing that truly exemplifies them, because it is beneath the dignity of biography, or at variance with received notions of their character and the tendency of their public conduct. The desire to have a closer view of the fountain head whence the outward manifestations of a great intellect have sprung, is but one of the many examples of man's spirit of inquiry from effects to their causes; and the desire will not be gratified by reproducing the object of inquiry in all the pomp and state of his public intercourse with the world, and keeping the veil still closed upon his inner nature. It is difficult to write with mere descriptive impartiality, and without exhibiting any bias of opinion, on matters which are, at the same time, the most deeply interesting to mankind, and the objects of their strongest partialities. Though the task that was before me was simply to describe, and never to controvert, I do not profess to have avoided all indications of opinion in the departments of the work which have the character of original authorship. I have the satisfaction, however, of reflecting, that the documents, which are the real elements of value in this work, are impartially presented to the reader, and that nothing is omitted which seemed to bear distinctly on the character and conduct of David Hume.