Just 12.2mm slim (measurement excludes lens cover), which is smaller than the thickness of a standard AA-size battery, the Cyber-shot TX55 is the world's thinnest camera in its class (among cameras with an optical anti-shake function).
If you move up slightly in size to Toshiba's Portege and the Gateway 3100, you get something closer to a standard keyboard and notebook configuration at slightly more than an inch in thickness.