I try not to get too worked up over the hassles of airport security. Officials are well-intentioned and trying to provide a crucial public service. Fine.

But when federal officials maintain travel records on Americans that keep track of everything from destinations, to travel companions, to reading materials, one can't help but wonder if some reasonable lines are being crossed.

The U.S. government is collecting electronic records on the travel habits of millions of Americans who fly, drive or take cruises abroad, retaining data on the persons with whom they travel or plan to stay, the personal items they carry during their journeys, and even the books that travelers have carried, according to documents obtained by a group of civil liberties advocates and statements by government officials.

The personal travel records are meant to be stored for as long as 15 years, as part of the Department of Homeland Security's effort to assess the security threat posed by all travelers entering the country. Officials say the records, which are analyzed by the department's Automated Targeting System, help border officials distinguish potential terrorists from innocent people entering the country.

The Automated Targeting System isn't exactly new; it's been used to screen passengers since the mid-1990s. Apparently, though, officials are monitoring personal travel habits in a way that hadn't been acknowledged before.

Take a look.