I mean, you gotta wonder: Is Humptulips as vaguely rude as it sounds? Who or what was Sedro Wooley? Who fought whom at Battle Ground? Did Startup get its name because that's where you 'start up' into the mountains (and what if you're coming the other direction)? And what about the whole Snohomish-Skykomish-Swinomish-Suquamish-Skokomish-Sammamish mess? This book is an excellent reference for getting to the bottom of it all. Not only cities and towns, but mountains, counties, rivers -- nearly everything with a name (except roads, bridges, and buildings) is listed here.
I do have to note, though, that although this book has been updated at least through the 1990s, it neglects to mention that King County, Washington, was 'renamed' in 1986. It no longer honors former US vice president William Rufus de Vane King, but is in fact now named after Dr. Martin Luther King, Jr. (this is true; you can look it up). Apart from that oversight, though, I recommend this title highly for people like me who can't help wondering why where they are, is what it is.