Hold on!!! Before this please read the common design principle post. After a long time thought of writing a post. Actually these days I'm reading a book which is written by Scott Millet and the name of the book is "Professional ASP.Net Design Patterns". I can guarantee that this book give you a great knowledge on design stuffs. Most of us are bit lazy to read things, so I thought of posting the things that I got form it. This is like the cream of what I got. I'll start it with the S.O.L.I.D design principles: The term S.O.L.I.D. comes from the initial letter of each of the five principles that were collected in the book Agile Principles, Patterns, and Practices in C# by Robert C. Martin, or Uncle Bob to his friends. Simply this is a collection of best practices for object-oriented design. Following will explain all the principles: Single Responsibility Principle (SRP) This principle is closely aligned with a common design principle called Separation of Concerns. It