What are doctypes and how do templates and blueprints fit into?

Question

What are doctypes and how do templates and blueprints fit into?

Answer

Have a look at Document Types and Templates to learn about doctypes, blueprints, and templates.

For an introduction to existing free doctypes jump to Doctypes Introduction or to Doctypes for alphabetical listings.

Name	Short Description
What are those Core Doctypes for?	Why should I decide to install the Core Doctypes?
How to use the Software Developer Doctypes?	I've installed the Software Developer Doctypes. How am I supposed to use them?
Why should I use the Doctypes for Agile Planning?	I am unsure of what the doctypes provided by the Agile Planning Add-on are used for. How are these templates useful?
What are the Developer Diaries for?	I have installed the Developer Diaries Add-on. How am I supposed to use them?