Who is Sibyl Johnston from Expecting Adam: A True Story of Birth, Rebirth, and Everyday Magic and what is their importance?

Sibyl Johnston is a writer and a good friend of Martha Beck. During Ms. Beck's pregnancy, Sibyl came to her home unannounced and just happened to bring many items that Ms. Beck had just been wishing for. Sibyl and Ms. Beck became good friends during this pregnancy as Sibyl often found herself caring for and supporting Ms. Beck through her difficult pregnancy. In fact, when Ms. Beck learned that Adam had Down syndrome, it was Sibyl that gave her much needed information to help her deal with the situation. Ms. Beck believes that Sibyl was an angel sent to her in a time of need.