Kevin Mitnick, the founder of social engineering, belong to the golden words:
Social Engineer planned to get the project (the source) of your new product for 2 months before release.
What's to stop him?
Your firewall? No.
Powerful system of identification? No.
Intrusion Detection System? No.
Data encryption? No.
Restricting access to the modem dial-in number? No.
The code names of the servers that make it difficult to define the location of the project the desired product? No.
The point here is that no technology in the world will not be able to resist social engineering attacks.
However, in part to protect themselves can still be - to learn than motivated by social engineer as he thinks and acts, what techniques uses. Knowing this, you can protect yourself from social engineering attacks. Details about this can be read in the book about Kevin Mitnick "The Art of Deception." However, since very few people read the book likes to watch film "Breaking", which is well illustrated techniques used by the Kevin.