Part IV includes a set of appendices that provide support for the main body of the book. Here we include coverage of related definitions (Appendix A), comparisons to other software development approaches (Appendix B), PBE tooling options (Appendix C), a visual view of the PBE Patterns and Guidelines (Appendix D), a pattern specification for the Subsystem Façade pattern (Appendix E), and a more in-depth look at the PBE Practice (Appendix F).