Library /sys$common/syshlp/decw$helphelp.hlb Glossary, Go back  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Pressing Go Back button displays the previous topic.

  Every time you perform a Visit Topic or Go To Topic
  operation, Help records the topic title. The list of
  titles that this creates is called a History. The Go
  Back button uses this history to display each previous
  topic as you request it.