Let me ask a question, "how often do you make it to the Shasta County area?" Yup, me neither but, I picked this little guidebook up from a bookshop in Mt. Shasta City, just in case. Truth be told the subtitle is a bit misleading as almost all of the routes listed are in the Redding / Anderson areas, either looping out into the country to the west, east, or south. Only one route goes up into the more mountainous areas to the north, towards Mt. Shasta and Lassen; that one exception does loop north, but only as far as Shasta Lake. There are also a couple longer, two-day routes along the I-5 corridor, and to Chico. The descriptions of each route are minimal at best, some are only a single sentence. The maps are good though, and there are turn by turn directions, as well as profiles for each. The routes range from 4.5 miles to 195 miles, though most are within the 20 to 50 mile range. It is a good one to have when you find yourself with some extra time while hanging around in Redding. There really is some nice country around there, and this book can help you find it.
Talken, Earl Biking the Best: A Guide to 24 of the Best Paved Bicycle Routes in and Around Shasta County, California [Shasta County, CA]: Earl Talken, 2008