RLS book rate-change certain to cover one's territory (8,6)
I believe the answer is:
treasure island
'rls book' is the definition.
I can't tell whether this defines the answer.
'rate-change certain to cover one's territory' is the wordplay.
'change' indicates anagramming the letters.
'certain' becomes 'sure' (synonyms).
'to cover one's' becomes 'is' (I can't justify this - if you can you should believe this answer much more).
'territory' becomes 'land' (land is a kind of territory).
'rate' anagrammed gives 'trea'.
'trea'+'sure'+'is'+'land'='TREASURE ISLAND'
Can you help me to learn more?
(Other definitions for treasure island that I've seen before include "R.L. Stevenson novel" , "work" , "... story by R.L. Stevenson" , "Robert Louis Stevenson novel" , "Book by Stevenson" .)