According to the Wikipedia article about Stephen King, one of the author's influences was Richard Matheson, author of I Am Legend, Hell House and other works. The article claims,
In a current edition of Matheson's The Shrinking Man, King is quoted as saying, "A horror story if there ever was one...a great adventure story—it is certainly one of that select handful that I have given to people, envying them the experience of the first reading."
Searching Amazon and WorldCat I have been unable to identify that edition. One current edition has appeared in the SF Masterworks series, but the results in WorldCat make no mention of a preface by Stephen King. The 2011 edition by RosettaBooks does not appear to contain a preface either. The 2001 edition by Gauntlet Publications has an afterword by David Morell but nothing by Stephen King.
What edition of The Shrinking Man contains a foreword or an afterword by Stephen King? Does that text also mention other works by Matheson that influenced King?