Place your cursor over Certifications and left click on the sub-option Task Books.
The top portion of this screen is display only. The information displayed was entered through the Person/Org menu option.
Select the person to which you would like to delete task books by left clicking on the Drop-down list button 
or by typing the person's name.
Find the task book that you would like to delete and left click on the Delete button 
on that target position line.
A dialog box will appear for you to choose either 
to delete the task book record or 
to not delete.