"The difference of effect between books which are not literature and those which are is that while the former amuse, entertain, and glance over the surface of the mind, the latter touch the deepest springs of being. Literature books touch us aesthetically, it is true."
* source; 'Talks on the study of literature' by Arlo Bates
While I think the sentence above has been transformed from "It is true that literature books touch us aesthetically.", What is the grammatic terminology for the case above where the whole extraposed subject clause has been fronted to the beginning among fronting, cleft sentence or dislocation? I guess this kind of structure would be one of "fronting".
The reference for my guess as "fronting" is from 'The teacher's grammar of English' by Ron Cowan, p.530;
(41) a. I don't doubt that he knows the answer. (that complement)
b. That he knows the answer I don't doubt.
Of course, (41) b slightly differs from mine, since it sill holds the subordinating conjunction 'that' without commas.
Would hope to hear your response.