Frommer's Portland day by day

Fodor's Pacific Northwest: Portland, Seattle, Vancouver, & the Best of Oregon and Washington (Full-color Travel Guide)

Portland Stair Walks (Travel)

Moon Oregon Hiking: Best Hikes plus Beer, Bites, and Campgrounds Nearby (Moon Hiking)

Oregon Day Trips by Theme (Day Trip Series)

Northwest Know-How: Trees

Day Hikes in Washington State: 90 Favorite Trails, Loops, and Summit Scrambles

Moon Pacific Northwest Road Trip: Seattle, Vancouver, Victoria, the Olympic Peninsula, Portland, the Oregon Coast & Mount Rainier (Travel Guide)

Pacific Northwest Birding Companion: Field Guide & Birding Journal (Complete Bird-Watching Guides)

Portland Birds (Portland Audubon), 2nd Ed: A Folding Guide to Familiar Species of Portland, Oregon (Nature Observation North America)