Compendium, compilation (6)
I believe the answer is:
digest
I believe this clue is a double definition.
'compendium' is the first definition.
(I know that digest is a type of compendium)
'compilation' is the second definition.
(I know that compilation can be written as digest)
(Other definitions for digest that I've seen before include "Periodical that summarises the news" , "Break down (food)" , "Assimilate - summary" , "Assimilate (mentally)" , "Summary or shortened version" .)