Solution

In order for a provider to show on the Appointment Book the following must be true:

1. The Provider is Active :  Go to Administration >> Clinicians  then click Get Data.
   Select the provider from the list and click on (Edit this Clinician's Details)

2. The Provider must be assigned to the Site you are looking at : Go to Administration >> Clinicians and click Get Data.
   (Selecting the provider from the list will display the list of sites the Provider is assigned to in the bottom data grid)

3. On the Appointment Book and if Day or Now view is selected, the Provider must be checked in the drop down list of Providers that is shown below the Calendar.