In aiding fugitive slaves the abolitionist was making the most effective protest against the continuance of slavery; but he was also doing something more tangible; he was helping the oppressed, he was eluding the oppressor; and at the same time he was enjoying the most romantic and exciting amusement open to men who had high moral standards. He was taking risks, defying the laws, and making himself liable to punishment, and yet could glow with the healthful pleasure of duty done. To this element of the personal and romantic side of the slavery contest Professor Siebert has devoted himself in this book. The Underground Railroad was simply a form of combined defiance of national laws, on the ground that those laws were unjust and oppressive. It was the unconstitutional but logical refusal of several thousand people to acknowledge that they owed any regard to slavery or were bound to look on fleeing bondmen as the property of the slaveholders, no matter how the laws read. It was also a practical means of bringing anti-slavery principles to the attention of the lukewarm or pro-slavery people in free states; and of convincing the South that the abolitionist movement was sincere and effective. Above all, the Underground Railroad was the opportunity for the bold and adventurous; it had the excitement of piracy, the secrecy of burglary, the daring of insurrection; to the pleasure of relieving the poor negro's sufferings it added the triumph of snapping one's fingers at the slave-catcher; it developed coolness, indifference to danger, and quickness of resource. The first task of the historian of the Underground Railroad is to gather his material, and the characteristic of this book is to consider the whole question on a basis of established facts. The effort is timely; for there are still living, or were living when the work began, many hundreds of persons who knew the intimate history of parts of the former secret system of transportation; the book is most timely, for these invaluable details are now fast disappearing with the death of the actors in the drama. Professor Siebert has rescued and put on record events which in a few years will have ceased to be in the memory of living men. He has done for the history of slavery what the students of ballad and folk-lore have done for literature; he has collected perishing materials.