All modern digital designs are done using behavioral hardware description language. This chapter introduces the essential elements to creating a design using code that describes what a design needs to do without specifying a detailed implementation. Operators, variables, and blocks are all covered. Operators are the symbols that indicate what manipulations are to be done. The different types of variables and when to use each are explained. Behavioral code is usually encapsulated in blocks, and the different options for blocks are also covered in this chapter.