Being a 22 year old, single, live in the islands, work one job, graduated school grandson I would recommend TMF's Money Guide to start then Money After 40 or one of the other books mentioned above. The money guide, while not the quickest read, would give her the answers to many of her basic questions that she may not know about being "only" 22. I've always been one to set the foundation for whatever I am doing. By knowing what certain terms mean, how taxes and fees affect returns, and how the market in general operates, allows me to better understand what it is I am doing with my hard earned cash.
TMF's Money After 40 gave me the eye opening needed for long term investing, and is still my favorite TMF book.

Here is my list of "Books to Read", not in any particular order:

>The Millionaire Next Door - Thomas J Stanley
>The Four Pillars of Investing - William J Bernstein
>The Richest Man in Babylon - George S. Clason
>Common Sense on Mutual Funds... - John C Bogle
>The Intelligent Investor - Benjamin Grahm
>A Random Walk Down Wall Street - Burton Malkiel
>The Random Walk Guide to Investing - Burton Malkiel
>How to Read Financial Reports - John A. Tracy
>Rules for Revolutionaries - Guy Kawasaki
>Buffett: The Making of an Adventure Capatilist - Roger Lowenstein
>What Color is Your Parachute? - Dick Bolles
>Investing in Real Estate, Fourth Edition - Andrew James McLean, Gary W. Eldred
>Confessions of a Tax Collector : One Man's Tour of Duty Inside the IRS - Richard Yancey

Best of luck to your grand daughter and her savvy grand parent.

-IF