Languages are like organisms, they do not appear by spontaneous creation, they evolve, and so it is with the particular terminology of biochemistry which, as I document here, largely derives from Latin and Ancient Greek root words. In the early part of the 19th century, when chemistry had shaken off the shackles of alchemy, new elements, new compounds, new techniques were discovered that needed names. It was the classical languages, Greek and Latin, to which these early scientists turned. As chemical approaches were applied to biology, much molecular terminology has also derived from these languages. In this book the common technical terms encountered in biochemistry and related subjects are defined and their derivation from root words in Latin and Ancient Greek explained.