What is TPP and what do you think about it?

Between the two political conventions, we are hearing about who is "for", and who is "against", the trans-pacific partnership.  But, this is one of the issues that is not being discussed in enough detail for us to understand it by simply watching traditional news coverage.  Here is just one article ... what can you find to learn more about TPP so that you can make up your own mind?

http://www.nytimes.com/2015/04/26/upshot/economists-actually-agree-on-this-point-the-wisdom-of-free-trade.html?_r=0