You can create multiple libraries. For example as a photographer, you may do some portraits and some events. You could have a library for each and in addition one for your own family photography. The library module has controls that allow you to search for specific types of photos; say you are a nature photographer and you want to find all of your shots of North American water fowl. Again, there is so much more to Adobe Lightroom than I could present in an overview.
In Develop mode, Adobe Lightroom has controls for adjusting the color and tonal scale of your photos. What is nice about this is the fact that all changes are recorded in the database and do not change your photo. Your instructions are stored and applied to your photo in memory, so you can experiment without affecting your actual images.
There is also a histogram panel that allows you to measure the color tones and make adjustments to the tones of your photo. You can fine-tune your colors with the Tone Curve. You can do split toning for coloring of monochrome images as well as doing special effects. You can adjust the sharpness and reduce noise with the detail panel and correct chromatic aberrations with Lens Corrections.
The Slideshow module is a method to present your photos with music and translations. You can create a template to customize how you want your slideshows to look. They can contain your identity plate on each slide. One thing that I don't like is that to distribute a slide show you have to export it to a PDF file, but then you loose the music. It would be nice if you could create a presentation and distribute it.
The Printing Photos module allows you to print photos and contact sheets. There are also settings that allow you to overlay images with text, photo information, and other options. There are pre-made templates that contain different layouts for diverse output. You can modify their settings to create customized templates. Overall, I like the print module, but it's slightly lacking: when I print a contact sheet, I like to put information on each header of the sheet so that I can quickly identify the information of the shoot. I would also like footer information such as page x of y, the date of the shoot as well as copyright information. And the ability to directly generate a PDF would also be nice; this is an Adobe product after all. I generate all of my contact sheets as PDF along with a color print, and right now it is still a manual process.