I Do Like Looking Through Illustrated Books,

about nature, 

particularly old ones like this one by Ernst Heinrich Philipp August Haeckel (February 16, 1834 – 1919) who was a philosopher, professor, physician, naturalist, biologist and artist, the title Art Forms in Nature, which is in fact a collection of his works published in 10 instalments from 1899 to 1904, 

 the book is so beautifully illustrated,

 each page and indeed each specimen,

 meticulously drawn, 

 so that future scientists can study minutely every detail,

 at the time photography was in it's infancy,

which is why detailed drawings and sketches like these were made, if you want to see more and indeed buy some of the original plates look here, and no I am not on commission, I am just absolutely amazed by his stunning work.