You can import contacts from Address Book on a Mac as either Clients or Contacts in Studiometry.
A. You can import Clients with contact information from Address Book by selecting File Menu > Import > Clients from Address Book
B. You can import a Client with contact information from a vCard or from Address book by simply dragging the vCard into Studiometry's client/project list in the bottom left of the main window.
C. You can import a specific Contact from a vCard by dragging it into a client's Contact list.
D. You can import a specific Contact from Address Book, vCard, or Delimited text by clicking the Import button while editing a contact or creating a new contact.