Casually try finding two books in valley (6)
I believe the answer is:
dabble
'casually try finding' is the definition.
I can't tell whether this definition defines the answer.
'two books in valley' is the wordplay.
'two books' means two replacements for 'book'.
'book' becomes 'b' (abbreviation for book).
'book' becomes 'b' (abbreviation for book).
'in' is an insertion indicator.
'valley' becomes 'dale' (dale is a kind of valley).
'b'+'b'='bb'
'bb' put into 'dale' is 'DABBLE'.
Can you help me to learn more?
(Other definitions for dabble that I've seen before include "Study or work at casually, not seriously" , "Tinker" , "Try something briefly and superficially" , "Treat superficially" , "Take dilettante interest (in)" .)