@Eunice L. , @Laith Ali absolutely has a point in there. She is correct that when leverage is evident or when one is able to stand his/her ground, then negotiation 'tactics' are moot. In fact, in many negotiation training sessions, the first lesson taught is that sometimes, you simply can't negotiate.
However, there are lots of gray areas. More than you can count. As a basic example, we're not always talking about money or inventory. Maybe a tenant or buyer is giving you a hard time about money, and you give up. After you both walk away, you may learn that they were more than willing to come to terms with your money, "if you only could have done this..." and sometimes "this" is something that would have been very easy and/or that you never would have thought to consider.
Another example-- think about the last time you had to make a deal with someone who inherently made you angry or uneasy. No matter what you did, it was hard to shake the little monster jabbing you in the pit of your stomach, right? Even if you could tell that they were about to say "uncle," you were more likely to want to squeeze them just a little harder. Whether you acted upon it or not, you wanted them to feel it just a little more than the person you met the week prior-- the one who approached you earnestly but respectfully and said he/she had a problem with your proposal that he/she was willing to try to work out with you.
You were looking for good negotiation books from the community, so, here's a quick list, in my opinion, of what a good book should cover:
Good negotiation books (and training) tend to focus on sound communication and extracting data so you can make everyone's life easier-- yours, and your adversarial partner's. They also focus on those emotions-- keeping yours in check whether you're the aggressor or the pursued. Good resources help you identify the most important pieces of the puzzle so you don't get caught up losing a good deal over a "Want" as opposed to a "Need" and no matter whether you're up against the jerk or the nice guy.
Good negotiation books and training are not about ways to over-use your leverage, to bully an adversary, or to get everything you ever wanted through scorched earth tactics. Instead, they provide ideas to think outside the box, to identify and maximize opportunities, and get to the table. The sole objective is-- without caving on the important pieces in your deal-- to get to the table.
Finally, a good book should focus a healthy amount on people-- every situation is different because the people driving the situations are different. Until you build rapport, you have no idea who's on the other side-- and even then, one of your most trusted confidantes can throw you a curve ball if something riles him/her on that particular deal, too. That's happened to all of us, whether the topic is a multi-Million Dollar real estate transaction or who's bringing dessert to a holiday dinner with family.
There are lots of other topics, but this is, in my opinion, what should be present at a minimum to be a 'good' book on negotiation.
If you are still looking for resources, you're welcome to PM me.
Happy New Year,
Steve