Of no subject is this more than administrative law [closed]
Of no subject is this more true than administrative law
Because this sentence is out of context, it is difficult to accurately explain the true meaning of "this" in relationship to administrative law or any other subject. That said, whatever "this" refers to may be somewhat true with other subjects, but is most true in relation to administrative law.
As to sentence structure, this is a copular inversion. The verb "is" links the subject to the prepositional phrase at the start of the sentence.