The textbook comes with a CD-ROM containing not only the full text of the book but a number of software packages which you'll need in order to do your homework. The software should run on either Macintosh or Windows; you may use whichever you prefer. One of the software packages, "Submit", requires Net access to submit your homework to an automatic grading program; an option in the program allows you to submit the homework to me for a grade, or to just check it so you can see what's incorrect and fix it before submitting it for a grade. Printed on the CD-ROM envelope is a "Book ID#", which you'll need in order to use the auto-grader, so don't lose it.