The above is a great web site and I copied and pasted the following from the above web site. This article sums it up really well.
Asperger's Syndrome has probably always been around, however, the medical establishment has only recently begun to diagnose it.
Dr. Hans Asperger, a Viennese pediatrician, wrote the first paper on the condition in 1944. He had been working with four children, ages 6 to 11, who had similar peculiarities. They were each passionately interested in one narrow subject, and would talk on and on about it.
Dr. Asperger believed these "little professors" had problems understanding other people. For example, they were clueless when their audience was becoming bored as they lectured about obscure subjects like growing peas, deep fat fryers or Richard III. They did not notice that people were yawning, looking at clocks, or trying to switch the topic. In addition, although the children could memorize facts about their subjects, they often had little understanding of it. For example, a certain child knew every obscure fact about the lives of U.S. Presidents and had no grasp of American history. They tended to be overly logical and rigid, sometimes moralistic in their viewpoints. They had trouble understanding metaphors. If a mother said, "I'm going to hop down to the store," her son with Asperger Syndrome expected her to leap like a rabbit.
As Dr. Asperger and others after him continued to study the syndrome, they were able to pinpoint other traits "Aspies" have in common. Some are clumsy and uncoordinated. They have trouble with self-care and tasks like tying their shoes or buttoning. Others have problems controlling their voices. They speak too loudly or in whispers; they have unusual inflections or monotones.
Many Aspies have trouble with sensory integration. They may overreact to loud noises or bright lights. They may be overwhelmed by the inside of a Wal-Mart with all the people, displays, lights and stimulation. They may cope with the stress by repeating certain behaviors to soothe themselves. Self-soothing may include elaborate rituals or "rules," such as wearing a certain item of clothing all the time or always eating from the same menu.
However, the trait that causes Aspies the most difficulty in life is their inability to pick up other people's social cues and to respond appropriately. Unlike autistic people, Aspies often are interested in other people and want to make and keep friends. However, they have to learn social interactions on an intellectual level instead of just picking them up naturally the way others do. For example, when a friend is wearing an ugly new shirt but seems very happy about it, most people will lie and say how nice the shirt looks. An Aspie may believe that the friend wants an honest answer to: "How do you like my shirt?" One six-year-old Aspie got in trouble when she told her grandmother that she was too fat to ride a bicycle.
For this reason, Aspies may constantly want feedback from the people in their lives. They may ask, "Did I say something rude?" because they really do not know if they did or not. There is a very endearing character on the television series, "Boston Legal", who is a brilliant lawyer with Asperger Syndrome. He carries around a little notebook with reminders like "Shake hands with your client after the trial," or "Thank the jury if our side wins." He always keeps his hands clasped in front of his body so he does not flap them around.
In 1994 Asperger Syndrome became part of the official "Bible" of American medicine, The Diagnostic and Statistical Manual of Mental Disorders (DSM). This is the big reference book doctors keep on their desks when they diagnose mental disease.
In order to be diagnosed with Asperger Syndrome, a person must show two of these problems:
"Marked impairment" regarding nonverbal social cues (doesn't make eye contact, doesn't understand others' body language, etc);
Failure to make friends;
Lack of appropriate social and emotional responses to others; or
Inability to spontaneously share enjoyment, interests and achievements with other people.
In addition, the person must show one of these behaviors:
An abnormal and intense interest in one subject;
Adherence to a strict set of rules, routines and rituals;
Repetition of certain mannerisms like hand flapping, hair twisting or even whole body movements
An obsession in the parts or mechanics of objects.
Asperger Syndrome is considered one of five "Pervasive Developmental Disorders" within the spectrum of autism. It is a lifelong condition and occurs in boys four times as often as girls. Because Aspie children are not mentally retarded, doctors usually do not diagnose them until they are in the early elementary school grades.