Take a photo of a barcode or cover
The copy I have was well used by whoever had it before me. The paper is yellow and falling out, but it adds to the mystique. It's amazing how these "old" books have tidbits of knowledge that doesn't show up in modern textbooks. So even though I have a biology degree with many botany courses, I can still enjoy and learn from an obscure general audience book. Between that and the feel of my copy, I feel like I have a hidden treasure.