Aspergers = Autism Spectrum Disorder?

Aspergers = Autism Spectrum Disorder? Why is Aspergers an autism spectrum disorder? I have a hard time understanding this. In my view, it seems Aspergers is very different than autism. They don’t even seem to be on the same spectrum. I wonder if in our lifetime, we will see these two diagnoses actually split into two separate entities. Honestly, I would like to see the two separate so more attention can be given to each diagnosis in its own right. Am I the only one who struggles with understanding how Aspergers is part of the Autism Spectrum?