Obviously, the 5th edition is dated wherever the author provides screenshots of things and discusses specific search engines or resource websites. Our library system didn't have the 6th edition, so 5h it is! (Amusingly, EBSCO's search interface is still pretty much the same! Though they are in the process of rolling out an update right now.) The principles are sound, and the exercises for the reader seem fairly useful. Plus, it's a short book and a quick read! It doesn't overstay its welcome.
Though I was somewhat entertained by a little bias slip of the author -- in her admittedly personal version of the answer to a question ranking the expertise of different people, she placed the founder of a marijuana legalization organization at the bottom of the five because that person wouldn't necessarily have expertise (not untrue), but also "their intentions are questionable." Ha! I bring this up because Quaratiello is a Republican representative in New Hampshire, and her campaign website includes the statement that she has voted against all pro-marijuana legislation there. It's always a little funny/surprising to encounter conservative librarians, a definite minority in the field.