Kathy has a whole series of hiking guides, one on each of the "main" islands (not to mention lots of places not even near Hawaii).  They are all good.  Here, she presents 43 hikes of varying difficulty and length that cover all areas of Oahu.  At the beginning of the book, she gives the potential hiker several chapters of basic "hiking in Hawaii" information that should insure that your hikes are enjoyable experiences and not disasters (like, would you even SUSPECT that you can get hypothermia on a hike in Hawaii ??).  The information on her hikes is very well organized and includes a table showing the type, difficulty and length of each hike.  Her maps and instructions for each hike are outstanding.  If you have a little extra time on Oahu and the inclination to take a hike, you will be very surprised at the depth of "getting away from it all" experiences that you can experience on Hawaii's most densely populated island!