Having a library of essential professional development books, magazines, and other learning content is essential. But, it can be expensive, especially if you do not know where to start. I have made my own mistakes, and it has cost me. While the money is difficult, the deerest loss is the waste of time. So, in the hopes of saving you time and money, here is my recommended library.
NOTE: I strongly recommend having these items in eBook (Kindle, Nook, etc.) format. Why? Because those formats are searchable, notational, and you can easy take them with you.
If you do not have a Kindle (or other eBook reader), start here.
(Book cost as of 15-Nov-2014 = $1,124.45 - eBook cost as of 15-Nov-2014 = $817.99)