WordPress Conditional Tags

The official definition of Conditional Tags, which can be found on WordPress Docs, is the following:

The Conditional Tags can be used in your Template files to change what content is displayed and how that content is displayed on a particular page depending on what conditions that page matches. For example, you might want to display a snippet of text above the series of posts, but only on the main page of your blog. With the is_home() Conditional Tag, that task is made easy.

WordPress Docs contain lots of informations on conditional tags and their employ; these are a must-read for every theme designer (at least a basic knowledge of php is required too).

On the web there are also some useful tips on creative usage of conditional tags. Here is a short list.

List of Conditional Tags on Wp.org;

The Ultimate Guide to WordPress Conditional Tags by Themelab;

How To: Use WordPress Conditional Tags to Hack Your Theme by WordPress Hacks;

About If Page Parent & Children Conditional Tags by Insitewebdesign.

Finally, there is an useful and popular plugin called Widget Logic, which makes use of Conditional Tags inside Widgets.