You may also want to see our page on Coding Concepts which has a section on Namespaces and Autoloading.
Composer
Required a page of its own. Please see our page on Composer.
Alternatives to Composer
- Tom McFarlin. Simple Autoloader for WordPress Project. 2017.
- Josh Pollock. Using a Class Autoloader to Improve WordPress Development. torque, 2015.