How Far Out Can the Ebbing Tide of SF Go?

From Author Wars - https://authorwars.com/books/how-far-out-can-the-ebbing-tide-of-sf-go-2080232.html

Overview:

Title: How Far Out Can the Ebbing Tide of SF Go?
Author: Andrew Porter
Year: 1991
Type: Essays

Editions/Publications:

Unknown. Science Fiction Chronicle, #142 August 1991 (Unknown, Andrew Porter, Andrew I. Porter, $2.75, 40 pages, quarto, MAGAZINE)