original work; the original
Refers to the original text, book, or publication as opposed to a translation, adaptation, or commentary. Common in academic and literary contexts.
To understand this paper, you need to read the original work.
I prefer to read the original rather than a translation.
original author
underlying work; original work
Compound of 原 (original) and 著 (work/writing). The reading げんちょ is the standard on'yomi combination.