Clean Code Development became popular by with the book "Clean Code" von Robert C. Martin and the formation of the Clean-Code-Developer movement.
Clean Code Development is a conscious development of software which is maintenable, failure resistent and efficient. The first topics are readability and understandability of source code when it comes to the avoidance of failures in implementation and the possibilities of later developments and developments in teams. Details about these topics can be found in the referenced book and on the web page of Clean-Code-Developer.
PureSol Technolgies helps its clients to learn and apply these principles by trainings and code reviews which are focused on these principles.