Not the scripts one.
It follows roughly series 1-3 with select episodes converging into a large story with extra tidbits of character background e.g. Mrs. Warboys is Jewish among other things.
You may be referring to the book by David Renwick, published by Isis (Large Pring) in Oxford, England. I found it through Amazon.com. Try them.
The book was first published in 1992 by BBC Books, printed by Hartnolls Ltd. in Bodmin, Cornwall. It might be out of print. My copy (second-hand but in perfect condition) came from a Kent County Council library. Good luck!
P.S. I live in southeastern Tennessee and was impressed by the speed with which Amazon.com procured my copy and mailed it to me ... for a ridiculously low price.