The author, Dr. Robert B. Cialdini, spent about three years applying for jobs and instruction courses at sales operators, telemarketing firms, used car dealerships and similar ones in order to observe real-life situations of persuasion - and all this was done undercover, meaning that he didn't tell his true intentions when applying for one of the jobs.

The book introduces six main principles of persuasion: reciprocity, commitment/consistency, social proof, authority, liking, and scarcity, whereas each of them is covered in a chapter. Each chapter explains in a simple way how different methods of persuasion work, supported by many examples, anecdotes and scientific studies.

Reciprocity: If someone received a favor she/ he will likely return one.

Commitment/ Consistency: When people commit an idea, goal or untertaking (either orally or on written form), it is more likely that they will stick to and honor it, even if the original motivations or reasons are no longer true or valid. This is because people tend to be consistent in their way of being and decisions for several reasons, which are explained in the book.

Social Proof: People often tend to beliefe what other people are doing or saying - especially if a lot of people are doing so. In on example mentioned, people gaze in the sky, and the more people are doing so, most probably other pedestrians will start to gaze too.

Authority: People obey authority persons, even if they order something, which is against ones personally principles, belief or moral. Two of the examples mentioned in this chapter includes the well-known Milgram experiments as well as the My Lai massacre.

Liking: People will accept an idea more easily, if it comes from a person they like. Therefore salesmen are often trained to dissemble interest in ones hobbies and interests and mirror body language and mimics for the very same reason. Tupperware partys are successful, because chances are higher, when products are offered from friends and people we know rather than from a salesman who's a stranger at all.

Studies also prove that attractive people can convince others more easily than people who are not so attractive.

Scarcity: Scarcity will raise demand on something. Therefore salesmen often declare products as only available for a limited time or in a limited quantity to create an artificial desire for them.

The reader will also get to know about different variations of those principles as well as countermeasures and how to protect oneself. The main reason why people can often get manipulated so easily is because of the world we live in, according to Cialdini. As it is full of information and everything has to go so fast, it's impossible to make all of our decisions based upon our concious decision-making process. Instead we rely on processes and decisions we have created throughout our life - shortcuts - in order to make life easier for ourselfs (click, whirrr). Predators exploit those then to fit their needs.

It's about persuasion in general. If I remember correctly, there's not one example related to it-security.