The following text is from notebook files of the program Mathematica. Notebooks are the files that the user of the program creates by typing text. The typed text forms cells that perform different functions, depending on their attributes. Notably, only input cells can be evaluated, which means that only input cells trigger the mathematical manipulation powers of the program. The result of the program's computations are presented in output cells. By default, new text becomes an input cell and the default output is an output cell that is placed below the input cell. The remaining cell styles function akin to the styles of word-processing programs, specifying the typeface and size of the text. In all cell styles, Mathematica has the capacity to produce the atypical symbols and text placement of mathematical expressions.

Users can also create packages that are files with resources that notebooks can invoke. Because this is an advanced feature that obscures the computational steps from the reader, the notebooks of this appendix do not invoke packages with two exceptions. They do invoke built-in packages, such as ContinuousDistributions.m, the package that gives Mathematica the functionality to handle some specific probability distributions that are continuous, such as the normal distribution (discussed in Chapter 9) or the lognormal distribution (mentioned when discussing option valuation in Chapter 11). Also, some of the notebooks that do produce three-dimensional graphics invoke the package Text3D.m, which I have authored and is available from the Web site of Mathematica's publisher, www.wolfram.com.