You can supplement your required reading with the optional book for this classs, Northwest Exposures: A Geologic Study of the Northwest, by Alt and Hyndman. Northwest Exposures is not required reading for this course.

You need to be aware of the scientific shortcomings of both of Alt and Hyndman's books on the geology of the state of Washington and the region of the Pacific Northwest, Northwest Exposures and the Roadside Geology of Washington.Those two books are not entirely based on sound science and are not authoritative. In both books, Alt and Hyndman have left some possible mistakes uncorrected. A flaw in Northwest Exposures is that Alt and Hyndman include in the book their hypothesis that a giant meteorite impact caused the eruption of the Columbia River Basalt, a hypothesis which is testable, has been tested, and has been discredited. As for Roadside Geology of Washington, it was written in the mid-1970s, so it is a book that is scientifically out-of-date. Other difficulties in old Alt and Hyndma   Roadside Geology of Washington are its nonstard names of accreted terrane groups such as "North Cascades Microcontinent," which is not a valid terrane group, and its outdated geologic time table, which still referred to the Tertiary period instead of the Paleogene and Neogene periods. Another issue in the Roadside Geology of Washington are the authors' statements on the location of previous subduction-zone trenches and the timing of terrane accretion, a topic which you might not yet recognize the meaning of, but which is important in understanding the geology of the Pacific Northwest. For example, they portray the Okanogan Valley and Okanogan Fault as a fossil trench of a subduction zone, which is not correct. 

On the positive side, many parts of Roadside Geology of Washington, other than the mistaken parts about the timing and nature of accreted terranes and ancient plate boundaries, and most of Northwest Exposures, besides the disproved meteorite impact speculation, are essentially correct. In fact, the Roadside Geology of Washington was a classic in its day, and has helped many people understand and experience the geology of Washington state, which is great, and the authors of the book deserve credit and honor for that accomplisment. It's just out of date as a science reference so now you should use the new edition by Miller and Cowan.       

There is now a new, up-to-date edition of Roadside Geology of Washington available, by Miller and Cowan. It is recommended for geology fans who want to keep track of the geology and stop and take a look and understand it while driving aound the state, or just read about it and imagine driving to the locations, which are well illustrated and shown on geologic maps in colorful detail.          

There are also a few other books you can read about the geology of the Pacific Northwest, including Geology of the Pacific Northwest by William and Elizabeth Orr, and The Restless Northwest: A Geological Story by Hill Williams.