Instruct: Classify the given Amazon review as either positive or negative.
Query: Strong cross-platform reference.

I have thousands of dollars in computer books. And as a network security analyst, I used most of them often. But I carry this book in my bag all the time. Since I work in a mixed environment, this book proves invaluable in helping me tackle Solaris, Linux and HP-UX issues. I have not seen another book that covers so much so well in less than 1000 pages. If you use unix, get this book. It will be among your top 5 books in the "best money spent" category!