Mozart's Requiem is without a doubt his masterpiece, one can only imagine how it may have been had he a chance to finish it. This edition indicates which parts of the score were written by Mozart and which were by Sussmayer, his student. Any musician would agree that seeing the full score version of any piece can be insightful to the composers mood and thoughts when it was written., this in stark contrast to the popular trend among music publishers to condense an entire orchestral score into a keyboard/SATB layout.
I reccommend this book for musicians who have at least an basic understanding of musical notation. The layperson would likely be unable to do much other than stare at the pages. But for anyone who can follow along, it's always fun to read along with a recording and notice new flurries and nuances every time!