One hundred days into the second term of President George W. Bush, a clear national security agenda and policy team have emerged. While there has been some change--most notably, the elevation of Condoleezza Rice to secretary of state and primary policy pilot--there is also a great deal of continuity, particularly in the Pentagon, where Donald Rumsfeld still rules supreme.

In addition to fighting wars in Afghanistan and Iraq, the defense secretary is leading the charge on a third front--the internal fight to transform the US military. Yet two recent books by experienced war correspondents tell important stories that call parts of the transformation program into question.

Here's a doomsday scenario worth considering.

It comes from David Poltrack, head of research for CBS, who happens to believe that, over the air network television will thrive for the foreseeable future. However, he warns, woe betide those who would dismantle it, because what is at stake is nothing less than the American way of life.

DAVID POLTRACK: And if, in fact, that current system deteriorates to the point that advertisers and marketers abandon it, I don't see anything that's going to replace it in the entire marketing infrastructure of the country, and the economy is going to be diminished, and that's a lot bigger problem than just a network television problem. [CLIP FROM OH BROTHER, WHERE ART THOU? PLAYS]

Who would have thought a book about punctuation could cause such a sensation?

In order to determine whether you are interested, tell me your facial expression when you hear these terms:

Hexaflexagons; Conway’s Game of Life; magic squares; Penrose tiles.

If you’re smiling, you're in. If you’re puzzled, read on. If you're groaning in irritation, forget it.

The Mathematical Association of America has just released the entire collection of more than 300 of Martin Gardner's columns for Scientific American, all on a single CD.

The cone of silence, called Babble, is actually a device composed of a sound processor and several speakers that multiply and scramble voices that come within its range. About the size of a clock radio, the first model is designed for a person using a phone, but other models will work in open office space.

Babble, which is intended to function as a substitute for walls and acoustic tiling, is an example of a new class of product that uses computing technology to shape sound.

The system will be introduced in June by Sonare Technologies, a new subsidiary of Herman Miller, the maker of the Aeron chair, as part of an effort to move beyond office furniture.

The company hopes that some of its designs will lead to spinoff companies that will be profitable for the investors.

One of the prototypes closest to becoming a candidate for a spinoff is a novel tabletop digital map, about the size of a large flat panel television. The system has a touch-sensitive screen, making it possible to handle high-resolution digital imagery as easily as sliding a paper map across a table.

The system is controlled by a series of hand gestures. For example, to zoom on a region, a user touches both hands to the screen and slides them apart.