Good book, first rate on Tube (5)
I believe the answer is:
hosea
'good book' is the definition.
(I've seen this before)
'first rate on tube' is the wordplay.
I cannot really see how this works, but
'first' could be 'a' (first letter of the alphabet) and 'a' is located in the answer.
'tube' could be 'hose' (hose is a kind of tube) and 'hose' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for hosea that I've seen before include "OT prophet/book" , "bookmaker" , "OT prophet" , "Book of prophecies" , "Minor prophet and book of the Old Testament" .)