Principles abound our lives. Software and engineering is no exception. The more you develop software, the more patterns and principles you master. Yet, solutions remain difficult to maintain and developers are frequently frustrated by impediments they introduce and the waste generated to get around them. But why do we run into these roadblocks? It could be that you're not using the principles of object-oriented development to build better solutions. The SOLID principles are an important foundation for how to leverage OO languages to produce high value, low overhead, maintainable solutions. Whether you've just starting to sling code or have been a veteran in the industry, the principles taught in this presentation are invaluable.