Illustration of the Tree of Life showing the rough relationship of the different Classes of the animal kingdom.
Thomas Alfred Brock (1872 – 1939) / Public domain
Frontispiece for "The wonder world we live in" (1917) by Adam Gowans Whyte. (Published as "Wonder Stories for Boys and Girls" in the UK).
Remember to use DELCAT to find more library resources related to your research topic. Place quotation marks around keyword phrases (e.g., "molecular biology"). Also try adding the word 'dictionary', 'handbook' or 'encyclopedia' to find a general reference source.