The Intersection: gripping stuff penned by novelist (5,8)
I believe the answer is:
level crossing
'the intersection' is the definition.
(level crossing is a kind of intersection)
'gripping stuff penned by novelist' is the wordplay.
'gripping stuff' becomes 'velcro' (Velcro is a material for attaching things).
'penned by' indicates putting letters inside (inserted letters are penned in).
'novelist' becomes 'lessing' (Doris Lessing).
'velcro' inserted into 'lessing' is 'LEVEL-CROSSING'.
(Other definitions for level crossing that I've seen before include "Point of intersection of a road and a railway" , "Road-rail intersection" , "Where a road traverses a railway" , "Here motorist comes by train" .)