The Canon Cat was an advanced computer designed mainly for word processing by Jef Raskin, the originator of the concept of the Macintosh. This computer, while often written off as a word processor only, was actually extremely advanced - it had a 300/1200 baud modem for quick transfer of files, an integrated programming language (FORTH) and a user-friendly interface with contextual help system.
As a word processor it was very good, however. It had a WYSIWYG interface when such were not common, a daisy wheel printer that produced beautiful text, and (mainly distinguishing it from "true" word processors) the ability to save files to 3.5" disks (more easily than any other computer, I might add - saving was a 1-button operation that stores the entire contents of memory to disk; loading was the other way round) and to transmit files long distances with the internal modem.
It was unique in two ways - the innovative, text-based user interface, and the fact that it had no bugs. None.
Programs for the Cat could be written in the Forth language and simply and easily executed by highlighting them and hitting a key combination. Though the Cat did not sell many units since it only ran for six months, there were a few Forth programs out there for it.
Specifications:
Released 1986, ran till early 1987
Motorola 68000, 5mhz
256k RAM
256k 3.5" floppy disk drive
300/1200 baud modem
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I got my Cat free (!) off Craigslist some time ago with all the accessories - it really is a beautifully designed machine. It's a pity that the thing was marketed wrong; professional writers would have loved it, but it was marketed to secretaries. The printer makes an astounding amount of noise, far more than a typewriter, but it's a great printer and as far as I know you can still buy ribbons for it. BBSing on it is pleasant and saving text files is very easy. All in all, a nice machine if you can find it cheap, but not worth the $1000-2000 prices they run to on eBay (I kid you not.)