[Excerpt] From the outset of my career in teaching, I have been deeply interested in the question of freedom. This interest is in part due to my upbringing and in part is the result of my academic training. Not only its substance but its origins, extension, and preservation have been abiding concerns. We often take freedom for granted, but quarrels and fights about its nature, conditions, and scope fill our history. Freedom had to be won. It was never, and is not now, established universally. It has had to be gained by groups who did not enjoy it. Such extensions as have been made were only by power of those who sought it. Freedom not only has had to be fought for, but, once gained, it has had to be maintained through constant defense. Eternal vigilance is the price of freedom.