Now who said this: "Opinions are the cheapest commodities on earth" ... ? I think it was Earl Nightingale talking about Napoleon Hill ...

Why not just split test it and let the customers decide ?

After all - the choice of a customer that voted with his money is as clear as a bell.

It is easy - and free- to set up in Google Website Optimizer ...
google.com/websiteoptimizer

Send traffic to the offer and see which one wins ...

You could also use a survey tool to ask the people on your mailing list, but the results from people buying will be of more value.

Or if this is a physical test, just print up brochures/books with the different titles and see which one moves off the shelf fastest.

Now for the opinion part ... lol ...

I remember reading somewhere about the addition of the "the" adding more authority - but I do not remember if it was just an opinion or the result of a test ...

Melvin Powers at mpowers.com has a lot of titles with and without - and those are books sold by direct marketing.

Another thought - a lot of the winning headlines in Victor Schwab's book started with "How to ..." . So that could be an approach.

Or how about instead of making a statement, turning it into a question ? On the lines of "Do you know these 10 .... whatever things" ?

This is definitely something to test for response in the marketplace, I think.

Good luck with it,

Conrad