Records there's something missing from the yearbooks (6)
I believe the answer is:
annals
'records' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for annals that I've seen before include "History of events year by year" , "Historical records" , "Chronicles" , "Yearly records" , "Record of events year by year" .)