Within double quotes, all special characters are interpreted as their ASCII characters (not what they represent). This excludes the dollar sign ($) and the back quote (`).
Adding to the above example,
sh_prompt> echo VARI = $VARINOTE the spaces in the above example: they are printed as seen (spaces are significant within quotes).
VARI = me
sh_prompt> echo "VARI = $VARI"
VARI = me