This, from the FAQ: Unfortunately, we are unable to offer upgrade discounts. This is due to the following: * The sheer amount of work that it has taken to upd

This, from the FAQ: Unfortunately, we are unable to offer upgrade discounts. This is due to the following: * The sheer amount of work that it has taken to update and revise the book. We have had to take significant time off from consulting in order to get the 1.6 edition done on time. The effort involved in putting together the 1.6 edition is equivalent to a whole new book in itself. * The inability to offer discounts to specific readers on print books through Amazon.com. Offering discounts would require us to manually coordinate payment and ship books one at a time, which is impractical. * We need to be able to cover our costs for printing a significantly larger book, and for working with multiple printers and fulfillment warehouses around the world in small quantities. We have been shouldering quite a bit of financial risk with international logistics and wholesale printing orders.