I ordinarily type my columns. But since this column is about tablet computing, I decided to compose it in longhand on the Compaq tc1100 tablet computer that Hewlett-Packard lent me earlier this year.

For people who never learned typing, or for those who find it a painful chore, writing on a computer's screen and having your words turned into beautiful text must be a liberating experience. I'll never know: I learned to type when I was in ninth grade and can easily crank out 120 words per minute. Still, Microsoft's Tablet PC edition of Windows XP has a handwriting recognizer that's nearly flawless. This computer was able to recognize my weird mixture of printing and cursive the very first time I picked up the stylus: neither I nor the computer required any training. The tablet PC could even recognize my seven-year-old daughter's handwriting-misspellings and all! In fact, it corrected each word as she went on to the next.

Driving this high-quality handwriting recognition is an incredibly rich dictionary (built from millions of handwriting samples), spelling and grammar smarts, and software that takes into account not just the electronic "ink" left on the page but the movement of the pen as you write. None of it would be possible without today's fast processors and huge memory chips. Computer hardware just wasn't up to the task a decade ago, when Garry Trudeau lambasted the Apple Newton in Doonesbury. Today the tables have turned.

But while entering text is a joy with this computer, going back and editing it is painful. It's easy to correct the occasional mistake that the recognizer makes by selecting the word and then choosing an alternative interpretation from a pull-down menu. Serious moving around of words or ideas, though, is better left to the keyboard. That's because precision counts when editing, and it's all too easy, when wielding a stylus, to get a punctuation mark wrong or flummox a word into something that looks the same on the tablet PC's small screen but has a completely different meaning.

That's why just about every tablet PC on the market today has a keyboard hidden underneath the writing surface. Just lift up the screen, spin it around some hidden hinge, and-voil!-you have a traditional (albeit expensive) laptop computer. And from my people-watching around MIT, it seems that tablet PCs spend a large part of their lives serving as traditional laptops, with the stylus snug in its holster while the keyboard gets a vigorous workout.