1) Author 2) Compiler 3) Encyclopaedist 4) Writer 1) Compiler 2) Encyclopaedist 
• (n.) The compiler of an encyclopedia, or one who assists in such compilation; also, one whose knowledge embraces the whole range of the sciences.
En·cy`clo·pe'dist noun [ Confer French encyclopédiste .] The compiler of an encyclopedia, or one who assists in such compilation; also, one whose knowledge embraces the whole range of the sciences. The Encyclopedists , 
[n] - a person who compiles (or writes for) encyclopedias
encyclopedist 1. A compiler of or writer in an encyclopedia. 2. One who attempts to deal with every branch of knowledge, or whose studies have a very extensive range.
encyclopaedist noun a person who compiles (or writes for) encyclopedias
a compiler of or contributor to an encyclopedia. · (often cap.) one of the collaborators on the French Encyclopedia.