You can PhotoRead the same book ten times a day. They can be activated in the future. If you have 20 books. I suggest PhotoReading 5 of them every day. Are they textbooks?
For activation. What's your purpose? If you are having trouble with activation you probably don't have a purpose. Also learn PhotoReading on a small book of about 250 pages first. Use the 5 day test as instructed in the book for 3 to 5 books before graduating to textbooks.
Alex