Correspondence courses are classes which are completed with course material and assignments mailed the 'old-fashioned' way between the instructor/grader and student. It is also possible that email may be used instead of physically mailing assignments. It is implied that the course material to be studied is in a physical book rather than exclusively on a web site, but it is possible that some course content may be found on one or more web sites or on floppy disks or CD-ROM.