This chapter is all about legacy code. If you have never had to deal with legacy code, count yourself lucky and know that it is coming. Some of you may be permanently stuck in maintenance development. Your life is legacy code. Whatever the situation, this chapter is all about dealing with legacy code. We want to either prevent legacy code from happening, or fight it back to the depths from which it came. 

In this chapter, we discuss:

• What makes code legacy
• The issues that legacy code can create
• How legacy code can inhibit testing
• What we can do to deal with and fight back against the legacy problem