Workbooks can deliver desktop popups or emails or a combination of both and depending on whether or not you are logged in.  To set your preferred method, go to Preferences > Notifications and Reminders and select your preference from the dropdown picklist next to Notification delivery preferences.  Possible preferences for notifications are:

• Popup my notifications on the desktop
• Send my notifications by email
• Popup my notifications on the desktop and send them by email
• Send my notifications by email if I'm not logged into workbooks
• Don't send me any notifications

If a meeting has been scheduled using a Workbooks activity, you can set the length of time prior to the meeting that a reminder notification will be sent to you. Similarly you can specify the default settings for activity reminders. Select your preferences using the dropdown picklists next to Default meeting reminders to occur and Default activity reminders to occur at.