Some items in Discover look to be books or articles but are in fact book reviews (it might include book / book review in the article title).  These reviews may not be accessible via Discover (a known supplier issue). However, book reviews are probably of limited use, so you could instead search Discover for the book title, choosing the 'Print and eBooks' tab. Unfortunately there isn't a way to filter out 'book reviews' from Discover, so please ignore them if they are not relevant.  

If you do want to access the book review article search directly via the journal supplier.

Please see this example of a book review appearing via the supplier Wiley.