So long introduction to text, before contents of book, led oddly to Dickens character (6-3)
I believe the answer is:
toodle-pip
'so long' is the definition.
(old-fashioned term for goodbye)
'introduction to text before contents of book led oddly to dickens character' is the wordplay.
'introduction to' indicates taking the first letters (I've seen 'introductions to' mean this).
'before' says to put letters next to each other.
'contents of' means to look at the middle letters (I've seen 'content of' mean this).
'oddly' indicates anagramming the letters.
'to dickens character' becomes 'pip' (I can't explain this - if you can you should give a lot more credence to this answer).
The middle letters of 'book' are 'oo'.
The first letter of 'text' is 't'.
'led' anagrammed gives 'dle'.
't'+'oo'+'dle'+'pip'='TOODLE-PIP'
Can you help me to learn more?
(Other definitions for toodle-pip that I've seen before include "so long" , "Farewell (informal)" , "Farewell remark - dipole top (anag)" , "Goodbye (dated)" , "Take care" .)