Public domain information and works can be used by the public to create a new information product or e-book. They then can be used as a commercial product to be sold for profit.
However, a lot of people think that they can just use the book wholesale without doing much changes to the original material. If so, you cannot and should not put your name on it.
The secret is, if you want to put your name to the product, you need to ensure that you do the necessary changes, editing, re-layouts and re-organizations or mixing of materials before you can claim it as your own. You can even copyright it as your very own material. This is the fastest and easiest way to create a brand new information product.
As you can see, public information works can be used to save you much valuable time that you can divert to your marketing efforts instead. You will also save much need money and other resources as well. Most of the information is already available. There are actually millions of public domain works that you can exploit for profits.
Creating information products is one of the best products to create out there. Information is always needed and can be updated as necessary, unlike technology products that can go out of fashion or trend fast. Yes, some information do go out of date, such as how to fix a typewriter, but often you can re-package the information such as collecting vintage typewriters and how to maintain them.
The final tip for you is that do not limit your public domain works to written ones. There are plenty others such as films, movies, audio and even photos that you can leverage on!
The whole internet marketing game takes time to master, so learn from those who have been there to shorten your learning time, and avoid painful mistakes.