Missing Vignettes for reshape2

Running 2.15.0 on Slackware-13.1 with all packages in /usr/lib/R/library.
Package reshape2 is in the library but there are no vignettes seen by R. If
this is the result of something I did incorrectly, please point out how to
install the vignettes with the package.

   I can get help for melt and cast but no reference on how to access the
vignettes.

Pointer appreciated,

Rich