Do you agree? "In the last analysis, you cannot learn negotiating techniques from a book. You must actually negotiate"

yes. you should know what is the board / company desire, policy and target. you must practically present, convince and persuade the buyer/seller to the target or close to it.

"you only get what you negotiate not what you want"

Negotaition can be learnt.... That is a fact. 

However, As everything you learn, you need to put it in practice in order to "Master" the recently acquired knowledge.  In other words, you might try to learn something, but without practice you cannot really apply it.

 The following link is a chapter of a very interested book about learning ( learning negotiation) written by Scott Peppet and Michael  Moffit. 

Learning How to Learn to Negotiate

Yes I agree .

And in my opinion always in any scope of life,  the  knowledge and experience are support each other .

In neggotiation you must give imperassion that you have a lot of options other than your second part, and if your supplier would not supply even than you can manage it easly.

Khalid Rabbani

Negotiation is a skill so reading information is not sufficient to be well skilled but you need to be trained to transforme your information ito skill then you need to negotiate and negotiate to sharp your skill