Michael -- I have the 1992 GPTS hardback edition (as opposed to the 2006 RCM softcopy edition). It is not in print any more; however, there are several copies available from used book distributors. All of the booksellers in question that I looked at just now are in the UK. If you search for the title and "lachman" as author at bookfinder.com, you'll see two hits, click on the second and you'll see the available copies that I found. Hope this helps.
