Negotiation methods

I here at work needed the skill of work with clients and ability to conduct negotiations. Up to this point, I was focused only on the financial analysis and did not take into account another part of this business at all - negotiations and process of the conclusion of transactions.
The last experience showed that ability to communicate with clients not less valuable, than the ability to find the prospective company for investment.
As well as always, I solved approach it from studying at the base.
To be advised to read the book "It is possible to agree about everything! How to try to obtain a maximum in any negotiations" the author Gavin Kennedy.
Here reference to profile:
https://www.livelib.ru/book/1000686893-dogovoritsya-m.
If to whom it is interesting, I can throw off the e-book.