Book big attraction all the same for the foolish? (5,6,4,2,5)

I believe the answer is:

where angels fear to tread

I'm a little stuck... Click here to teach me more about this clue!

'book' is the definition.
(novel by EM Forster)

I don't understand the remainder of the clue.

(Another definition for where angels fear to tread that I've seen is " Here fools rush in (5,6,4,2,5)".)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app