The Olive Oil Source
If you can't find what you want to know about olive oil at Olive Oil Source, the info may not exist. I enjoyed reading the detailed steps to sampling and evaluating olive oils that are similar to wine tasting rituals. Download a tasting sheet that will guide you to distinguishing color, aroma and flavor attributes. The site offers useful info on cooking with olive oil, such as a conversion chart from butter amounts, as well as olive oil's health and beauty attributes. Looks through the many events and competitions centering on olive oil.
I know folks who moved into homes with existing fruiting olive trees and decided to make the best of the situation by curing the olives! Although not technically a book, University of California's Division of Agriculture and Natural Resources offers a free publication that details everything you need to know to cure olives safely. Olives: Safe Methods for Home Pickling explains when to harvest for various uses, including a photo comparison of different stages of ripeness. The publication provides detailed instructions for making water-cured, brine-cured, dry salt cured, and lye-cured olives. Download it at http://ucanr.org/freepubs/docs/8267.pdf.