Google SEO - Importance of titles and Descriptions

After you've ensured that your site is both findable and accessible, don't let your great content languish with uninspired introductions.  Think of the titles and descriptions on your pages together as an advertising billboard: You have just a few words to let people know what each page is about and convince them that it's worth a visit.    
The title tag of your page is likely to be displayed anytime Google shows your page in its search results, and it's also what people will typically see in various places in their web browser and even on social sharing sites on the web.  Therefore, it's important to have a concise, descriptive title for each page on your site. 
Google may draw from several different sources for the descriptive snippets in search listings, including meta descriptions, so you'll also want to make sure your meta descriptions are thoughtfully drafted for each page on your site. 

Note that you can use Google’s Webmaster Tools’ “Content Analysis” feature to help you optimize your page titles and descriptions.