Waiting for a third printing is a mugs bet: HOP is a printed by Morgan Kaufmann, they may not issue a third printing unless there is a really massive demand for the second. The first printing of HOP was something like two-thirds pre-sales. A lot of people ordered it online with 'ship it to me when you get it'. That demand really surprised the folks at MK, they are not used to 'text books' selling out like Fiction. Unlike O'Reilly, they don't print in small batches, so they can't fold errata in at will.