Just so happens i am in the sales line, any sales book is good. Here i listed down some of my fav. I will give a brief explanation each one of them, you can choose who you like or based on what you need.
The psychology of persuasion by Kevin Hogan
This book is my recomended book for all my friends, why? Because it teaches you from the basic till the most advance technique . It makes you understand the whole cycle, from how do human thinks and how to use these infomation to your benefit. This book is also recommended to all DJ from NEWBIE to MASTER!!!
Selling yourself to others by kevin Hogan and William Horton
This book will add more infomation from his previous book, nothing much is new, but you add more depth in your new found knowledge.
Talk your way to the top by Kevin Hogan
Not too many new things to learn, just more hands on approach plus the excersize is a very good way to improve your talking skills. Plus it helps me alot about talking to chic with these books.
Covert Persuasion by Kevin Hogan
If you do not get his 2 or 3 book, it ok, this books cover it all from 1 till 3 plus more easy to use and more important, it has a great final chaptor to teach you how to use all the knowledge you learn so far in a situation. You need the first one though, if you planning to get his book, i personally will like you to get his first one, then go for this one. It will gives you more in depth knowledge on how human psychology works. This one is like a sequel to book 1.
You can read anyone by David J. Lieberman
This book is so cool, want to know when a lady is testing you, lie to you, show you the signal? Well this book my friend is what ALL DJ should read. I never got his first book "NEVER TO BE LIED AGAIN", but this one is good enough. This book helps alot, plus it so EASY to use his method. If you read the psychology of persuasion, these 2 books combine, you will freak the ladies out because you can almost read their mind.
Get anyone to do anything by David J. Lieberman
This is also a cool book, different than the first one, this one get the other party to do your bidding, again if you have read the psychology of persuasion, these 2 books combine, the other person wont even know that your manupulate them.
Is that your hand in my pocket by Tom Lambert and Tom Parker
This is book is more on business settings, very good book to supplement on what you already learn, and teaches you new things as well. I definatly recommend this book, if you are in sales, this book is great.
Sell your way through Life by Napolean Hill
This is a classic. The fundamentals on selling, if you are in sales, you must have one copy. Fundamentals dont change, technique will. Get your basic right and all is well, if you are not in sales still i recommend. Fundamentals dont change, technique will. This old school style dont teach you to flatter your way through life, in fact this books condems it, plus you get to see old school dj style in business settings.
The Sales Bible by Jeffery Gitomer
If you are in sales then this a great one to have, simple and easy to use. No nonsense bull****, in your face attitude.
Ok, i have many more but i wont list them all, i guess this is a good way to start, plus you can still check out Zig Zigler And Brian Tracy, these also my favourite author, why i did not included, their method is way out of style plus the fundamentals are also taught the books i mention above, so no need to repeat, unless you a book colector like me.Also any book about NLP are great, i dont get it cause Kevin Hogan already cover that part, but if you need more info about NLP you can always get one. They are great anyway.
P/S All the technique about manupulationg ladies in these forum works on men as well, just minus out the romance part your good to go. Plus after reading all the kevin Hogan books, you can understand WHY it works, HOW it works. On this part i am not jk. The exact science of kino is explain in his first book, you get the whole picture, whatever technique is use here, it all cover in his first book.
On a final note here, like all the technique we learn here, it can use for good or evil. Choice is yours, just like gravity, we manipulata gravity to fly a plane it destination or you fly a nuclear missile, which is it? The choice is yours. With that, be more concious how you want to manipulate a situation. I believe in a win - win situation, with these skill you certainly can develop you win - he lose situation. Again choice is yours, i just provide a way.