Hmm, reading the description on Amazon it seems like they have added more 'implementation' examples. For me at least I found better sources of implementation examples (the Bach book on UNIX for example) so I suspect, but can't confirm, that the newest one is probably not a whole lot better, and if you can find the 7th edition at a discount (or the 6th or 5th) you might be able to add it to your library less expensively.