Applied behavior analysis (ABA) is the application of the past hundred years of research into how learning works. It has universal application; it can be applied to any situation in which learning is involved. Recently, ABA has gained prominence in the teaching of children with autism-it is currently estimated to affect 1 in every 42 boys and 1 in every 189 girls-since, while there are many different approaches to treating autism, if learning occurs as a result of any of these different approaches, it will occur in keeping with the laws of learning on which ABA is based (you may productively think of it as remedial education for the social communications deficits that define autism). In addition, of the myriad of approaches to the treatment of autism spectrum disorders, applied behavior analysis (ABA) has the most research support and some of the best-trained therapists.