Particular form of a book (7)
I believe the answer is:
edition
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">particular form of a book</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for edition that I've seen before include "in printed form" , "I don tie (anag.)" , "copy of work" , "Copies of book printed from one set of type" , "Something impressed" .)