I spent about 15 minutes reviewing the materials. The content is excellent. The contents provided are useful as an addition to either an on-line or on-campus class. The site is effective as a learning tool. The site is easy to use, with the learner either using the back and next buttons or choosing a topic from a table at the bottom of the page. The only problem is that there are pop-up messages and advertisements throughout the site, even when one puts the cursor over a highlighted word in the text.