The Origin of Species, Charles Darwin (1859).
The famous evolutionary theory contained within the hundreds of pages of this biological epic can be described in only a paragraph. While the theory was revolutionary to say the least, reading through the pages of CD's own words offers a great look into a truly rigorous and critical scientific mind. Darwin's ability to influence thinkning and open minds to new ideas was likely in large part to the beautiful exploration of the arguments AGAINST his theory which he systematically deconstructs and ultimately uses to strengthen his position.
What is Life? Erwin Schrodinger (1944).
Leave it to a physicist to shake the foundations of science with three words and a question mark. I originally wanted to see what this book was all about because James Watson cited it as his inspiration to seek the structure of the gene. Unfortunately I don't totally know what it's all about yet because the first few paragraphs got me thinking about genetics so much that I set off on a tangent of reading basic genetics (see next title) and haven't yet found my way back to poor old Erwin.
Experiments in Plant Hybridization, Gregor Mendel (1865).
Reading this paper one is struck by the stark contrast between the massive significance of this work (ie the founding of modern genetics) and its sheer humility. A monk counting pea plants in his garden. It doesn't get any humbler than that. He also puts forward in these pages a great example of how to write a real scientific paper. Of course, no mention in the discussion predicting how his discoveries would cure the diseases of humankind, extend lifespan or save civilization...(nor are there any trojan horse analogies for that matter)
Signs of Life: How Complexity Pervades Biology, Richrd Sole and Brian Goodwin (2000). Before anyone was talking about "Systems Biology", this book attracted my attention for its elegant use of nonlinear and "chaos" mathematics to describe the weird and fascinating behaviour of biological systems ranging from viral quasispecies to ant civilizations to the human brain. By no means a fully-developed classic, but I though it was pretty cool at the time.
Viruses and the Nature of Life, Wendell Stanley, Evans Valens and others (1961). Fundamental virology by the people who discovered it. Written back in the day when there was no microarray or RNAi and viruses were still the sexiest and coolest thing out there, it's hard to read this little book even today and not come away thinking that viruses are the answer to everything. Even the black-and-white illustrations are great. If I ever taught a introductory course to virology I'd base it on this book. Also full of great general biological prophecy, for example, in cancer: "Huebner discovered that adenoviruses would destory the abnormal cells of cervical cancer in women...However, the virus could not destroy all the cancer cells before antibodies to the virus developed...Work of this general nature is only in its infancy...by selective cultivation of mutant virus strains, it should be possible to develop viruses which ignore normal cells but will have a special predeliction for the destruction of cancer cells." Hmmm...sounds kind of like an oncolytic virus...