What makes a great Production Assistant?

How great is the tagline for this book?:
The Production Assistant's Handbook: Because No One Has Time to Tell You What You Need To Know 

There are ways to make yourself indispensable on set. There are also ways to make yourself unforgettable (and not always in a good way). Caleb Clark put together this handbook because there are tons of things to learn at every stage in this business. Take a look at what he says in his intro:

"Like all entry-level jobs, the object of being a P.A. is to work yourself out of the job by making yourself too valuable to be kept in the entry-level position. Being a P.A. is also a weird test with only one question; Are you willing to become the best P.A. you can, even though you know that you won’t be a P.A. for long?"

This site also provides links to other valuable learning tools, where to train (online and in person), and how to get listed for a job.