Hebrides isn't quite the Holy Grail of Starmore books (that honor belongs to the Scottish Collection--don't even *try* to find that one for sale!), but it's very close. The rarity of this title is puzzling, since it's not actually that old: Celtic Collection and Fishermen's Sweaters both predate Hebrides, and those books are still relatively easy to find.
Hebrides is a lovely book, but I don't think it's worth the massively inflated prices it fetches here and on eBay. The collection's strength is the diversity of the patterns within its covers: there are Arans, ganseys, lace scarves and wraps, Fair Isle and intarsia colorwork, rugged outdoor wear, and one very cute hat. Noteworthy designs include the Rona and Roscalie cardigans (Roscalie comes in two different colorways, both attractive), the Sheilavig vest, the Malin aran pullover, and, for kids, the adorable Reef. The one sour note in this medley is the Keava sweater, a Fair Isle design in a screaming chrome yellow; but in a substitute colorway, even this pullover might turn out well. I also don't think the Seaforth gansey is equal to other gansey patterns published by the Starmores; it's nice enough, but nothing really special.
Buy this book if you can find it for a hundred bucks or less, but don't spend your life savings on it.