As part of a series, it works great. There is a summary of the previous book but it isn't glaringly obvious and obtrusive. It's subtle and fits really well into the story as it's narrated. As such, this would also work well as a standalone. But I'd suggest reading the first book too, because it is all kinds of wonderful and it will give you a better experience overall.
How much of my copy have I highlighted for awesomeness? About 90%. The only reason the whole thing isn't highlighted is it would have made my eyes go all funny. I've picked out quote after quote for so many reasons, from being hilarious to being awesome writing.
Sapphire is one of my favourite characters I've read this year. She gets herself into such situations... And she is so strong. Physically and mentally, she kicks butt and kicks it well. She juggles these two completely different lives and she still manages to keep it all together. I'm addicted to reading about her antics, to watching as she develops.
Silencing Sapphire is more brutal and shocking than Stalking Sapphire and still has that refreshing lack of graphic sex which makes it really stand out as excellent within the New Adult genre. This book doesn't need the allure of sex, it's perfect all on its own with fantastic writing and excellent pace. The pacing is just as subtle and gripping as in the first book, with the same jaw-dropping WHAT?! ending that leaves you desperately wanting to read more.