Children with Aspergers Syndrome have areas of special interest.  These are typically subjects in which the child has amassed some degree of knowledge.  This knowledge base provides a degree of security and familiarity for the child.  It is a topic in which predictability can be found. 

Special interests build self-esteem and reduce anxiety.  They provide security in an otherwise confusing world. 

Teachers can use the child's area of interest as a pivotal point for teaching new concepts.  By using the special interest as a subject, the teacher has an advantage in that she already has the student's attention and focus.