What is the ADC Bookshelf slots system?
Most Safari books fill up one slot on your Bookshelf; some fill half slot, two slots or three slots. Suppose you have purchased a subscription for a 10-slot subscription for one year. If you choose only 1-slot books, and swap aggressively, you can use 120 1-slot books during the course of the year. If your mix favors -slot books, you’ll have access to more than 120 books during the year. Likewise, if your mix tends toward 2-slot or 3-slot books, you will have access to slightly fewer books.