How well do you write? Even if you are not a professional writer, this is an important question. Whether you write fiction, business plans, website copy or merely email--clear, concise writing makes a difference. Modern word processors and browsers all have built-in spell checkers, helping with some of the more common mistakes. But even a typo-free text can still be cumbersome, vague, and overladen with cliché. StyleWriter Professional ($190) is a program that promises to help you whip your text into shape, making it leaner and crisper.

When you feed a document into StyleWriter, it quickly goes over the text and assigns it three ratings: the Bog Index, measuring how difficult your text is to read; Average Sentence Length, and the Passive Index, showing how well you use the active voice. Each metric gets a numeric rating, as well as a word grade (Fair, Average, Excellent, and so on). The three ratings appear on the status bar, letting you see at a glance how your text fared.

After initial analysis, it's time to drill down to the sentence level and start ironing out the kinks. You can either do this from top to bottom, or you can focus on more problematic areas first. To help you zoom in on trouble areas, StyleWriter offers a sentence graph: This is an interesting visual breakdown of your text that looks like a horizontal bar graph. Each sentence gets a single bar; bar length matches sentence length, letting you instantly see lengthy sentences. Difficult words increasing Bog Index are shown as blue squares in the bar. Unknown words (possible typos) are marked as red squares. And finally, gold squares mark "glue words:" These are the 200 or so most common words in English, excluding personal pronouns, used to link other words together. A high proportion of glue words means your sentence is too wordy, at least in theory.

You can customize StyleWriter to suit your style and needs. For example, by default StyleWriter highlights every instance of "it's" and "its," in case you sometimes mix them up. This is not a mistake I usually make, so I added an exception for this pattern. I was also able to add patterns: When my editor noted I misused "importantly" when I should have used "important," I added that as a pattern and copied my editor's style advice into StyleWriter. When I next use "importantly," StyleWriter will highlight that and remind me why that's probably a bad idea, in my editor's voice.

Even though StyleWriter's language engine doesn't always catch everything, it is very helpful. Other areas of StyleWriter could use some work, tough. First, StyleWriter is aimed at Microsoft Word users. It can't open files on its own: You must run StyleWriter from within Word. If you don't want to use Word, you can copy your text into the clipboard and StyleWriter will process it, but will offer less editing options.

Next, StyleWriter doesn't always play nice with Word 2010. When I had two Word windows open (one with a document and one without), StyleWriter picked the wrong window and tried to help me edit a blank document. Working with StyleWriter involves constant switching between StyleWriter and Word, and I had to fiddle with StyleWriter a bit until I could that to work like I wanted it to. Last but not least, StyleWriter uses an activation procedure which means if you install it on a new computer you must contact the company for a reactivation.

At $190, StyleWriter's Professional edition is a decidedly expensive application. The company also offers a Standard version for $150, and a Starter version for $90, but even $90 is not a modest sum. And StyleWriter is not a silver bullet for awesome writing, either: You will still have to work at it. But if you are willing to put up with StyleWriter's software quirks, customize it, and use it wisely--your writing will almost certainly be better for it.

--Erez Zukerman