Eg pianist’s assistant gripping book? (4-6)
I believe the answer is:
page-turner
'gripping book?' is the definition.
(I've seen this before)
'eg pianist's assistant' is the wordplay.
'eg' becomes 'page' (I can't explain this - if you can you should give a lot more credence to this answer).
'pianist's assistant' becomes 'turner' (I've seen this before).
'page'+'turner'='PAGE-TURNER'
Can you help me to learn more?
(Other definitions for page-turner that I've seen before include "Gripping book" , "'Unputdownable' book" , "exciting book" , "Book one can't put down" .)