When I checked Gateway by Frederik Pohl out of the library (it having been recommended to me by a librarian, based on the fact that my favorite book up to that time was Watership Down), I discovered something rather unusual about the text. The regular printed text ended with Robinette Broadhead finishing his last appointment with his computer psychoanalyst Sigfrid. However, another short chapter (one narrow column of small print) was taped into the back of the book. The passage seemed as if it had been cut from a magazine or something printed on similar paper, and it told briefly of Robinette meeting up with S. Ya. Lavarovna and finally seeing something of a worthwhile future before him.
I know that before it was published as free-standing novel, Gateway was serialized. Was the last chapter something that was published in the last part of the magazine version, which was subsequently cut from the novel (and restored by a diligent librarian)? Or, if not, what are the statuses of the different version of the text?