 In the past, mental privacy could be taken for granted: the first-person accessibility of the contents of consciousness ensured that the contents of one’s mind remained hidden to the outside world, until and unless they were voluntarily disclosed. Instead, the battles for freedom of thought were waged at the borders where thought meets the outside world -- in expression -- and were won with the First Amendment’s protections for those freedoms (note, however, that these protections are only against government infringement). Over the last half century, technological advances have eroded or impinged upon many traditional realms of worldly privacy. Most of the avenues for expression can be (and increasingly are) monitored by third parties. It is tempting to think that the inner sanctum of the mind remains the last bastion of real privacy.