Tensions between press and public being what they are these days, I hasten to perform the mandatory rite of full disclosure. Protection of sources, an important issue in this book, is more than academic to me.
In 1976 the House Ethics Committee threatened me with a contempt citation and possible jail sentence if I did not disclose where I had acquired an intelligence report that the House had voted to suppress. Happily, I prevailed.
Secondly, in 1994 Floyd Abrams defended me - successfully - in a libel suit. Abrams was retained by National Public Radio for the simple reason that he is the nation's preeminent First Amendment lawyer with a 37-year record of mainly successful litigation on behalf of newspapers and networks.
One might not have predicted that he would become the paladin of the press when he wrote an undergraduate thesis at Cornell arguing that it should be criminal to publish information prior to trial that might interfere with a defendant's right to a free trial.
But since then, as revealed in "Speaking Freely" - a recounting of some of Abrams's famous cases - he has come down most often in favor of free speech when measured against reasons to limit free speech.
In great and vivid detail Abrams guides us through the biggest cases, not all of them involving the press. They range from Abrams's victory against the effort of New York Mayor Rudolph Giuliani to purge the Brooklyn Museum of a display the mayor considered sacrilegious, to the lawyer's defeat in an effort to have the McCain-Feingold restrictions on political fund-raising declared unconstitutional.
But of all the cases Abrams so meticulously recites, the one that truly merits the overused adjective "landmark" is the 1971 Pentagon Papers case, the one in which, for a week, press freedom seemed to hang by a thread.
Do you remember or were you too young to know? A former Pentagon analyst, Daniel Ellsberg, disillusioned with the Vietnam War, made available to The New York Times and then The Washington Post a long history of America's involvement in the war. The Times had published part of it when the Nixon administration sought an injunction against further publication.
The issue before the US Supreme Court was "prior restraint" - whether the Constitution permitted the government to ban publication on grounds of national security. The Nixon administration argued that, if publication continued, "irreparable harm" would be done to US security.
Abrams and his onetime professor, Alexander Bickel, argued that prior restraint - advance censorship - was simply forbidden by the Constitution. The court struck down the injunction.
As I relived that First Amendment battle, I could remember the jubilation with which the decision was received in newsrooms around the country. It seemed to be about as unqualified a victory for press freedom as I could remember. Justice Hugo Black wrote in his opinion that "the press was protected so that it could bare the secrets of government and inform the people." Justice William O. Douglas wrote that the injunction constituted "a flouting of the principles of the First Amendment."
But, a generation later, reading through Abrams's narrative, it struck me the Pentagon Papers decision was not as unqualified a victory for the free press as I had thought. What mattered more than the individual opinions of the justices was the per curiam order of the whole court. And that document said the administration had not met the "heavy duty" of demonstrating why prior restraint was justified.
In other words, the court was not making an unqualified statement about the unconstitutionality of prior restraint but asserting that in this case the administration had not made a strong enough case. Another time it might be more successful.
And, sure enough, eight years later a federal district court banned the publication in The Progressive magazine of an article, drawn from public sources, of how to build a hydrogen bomb.
But, as Abrams notes, we are living in a different era, in "a world transformed by the Internet," a world in which an attempt at prior restraint may be "an especially pointless endeavor."
Imagine if Ellsberg had posted the Pentagon Papers on the Internet! Who would be Floyd Abrams's client?
• Daniel Schorr is the senior news analyst at National Public Radio.