Aspect Oriented Software Development (AOSD) is a methodology meant to implement new aspects in software component using external components, but without altering the code that implements the core functionality. The AOSD concept was applied originally by Java developers. They developed a compiler that implements the AOP (Aspect-Oriented Programming, an implementation of AOSD) white box approach, i.e. the compiler the merges the code that implements the software components core functionality with the necessary code alterations to implement the new aspects where necessary. This paper provides an introduction into the paradigm of aspect-oriented software development (AOSD). It includes a multitude of practical examples, provided with a view to objectify such abstract approach as AOSD, as well as to help the reader easily grasp its essence and advantages. The paper is primarily intended for programmers working with PHP. Its aim is to demonstrate a way of applying AOSD in PHP-based project