Maybe the theme you're using has created custom functions that make your code above work. As Sagive SEO notes it doesn't appear to be a valid tag. You'll need to just commit to learning the code if you really want to understand how it works. If you don't actually take the time to explore the core code, you never actually get it.
Someone may answer a question for you here and there, but you won't really understand the way things work.
Try exploring the WordPress codex pages. Another good way to learn is to open the WordPress core code. The documentation is very extensive, and seems to improve with every version.
Here are a few valuable links to the_author tags that might shed some light:
WordPress V3.0+Template Tag Reference Guide
Check out the PHPXref WordPress docs. They should help you out quite a bit. If you hover over a function, tag etc... you'll notice a pop-up with some descriptive text.
PHPXref WordPress docs