Hi Chandra,
decades ago,
I studied "The Science of Programming" book
and did most of the exercises.
I never missed an "Answer Book".
So why do you need it and/or search for it?
If you are about to learn the subject,
don't search for an answer book.
If you can't do an exercise of some chapter,
you probably do not yet understand that chapter,
so redo the chapter but don't look up the solution.
If you are about to teach the subject,
you have to be able to answer the exercises.
Astonishingly "Answer Books" are usually made available
to teachers only ...
Any case: Have you ever asked David Gries himself?
Diethard.