German naturalist Alexander von Humboldt helped popularized science texts with his book Kosmos, published in five volumes between 1845 and 1862, which gives an understandable account of the structure of the universe as known at the time. Around the same time, Gregor Mendel famously studied pea plants and laid the foundation for the modern science of genetics. Readers will be amazed by the detailed biographies of these and many other notable scientists, which are supported by amazing photographs and primary sources.