A few things to note -
Vi from Solaris 2.6, is the version used to verify the information presented in this publication; it is not the most up to date text. However, Vi is almost certain to be installed any server you might work on, so the commands contained in this booklet are almost guaranteed to work.
Coverage of Vim is rather poor, badly out of date, and pretty much pointless as Vim and Vi are now perhaps better than 98% compatible. Vim is to be greatly preferred where it is available. Similar editors are also given cursory coverage, but to be frank I've never seen any of them in the wild, so I won't comment.
The book is cleverly laid out and contains quite a lot of useful information for anyone who is already a Vi or Vim user. It is a little light on explanations, so not really for an absolute beginner (though the beginner could do worse).
If you are a complete novice I'd recommend typing "vimtutor" at your local command prompt when you've got 45 minutes of concentration time to spare.
Not a bad little book but a bit dated - OK