Complete Guide to PC File: Through Version 5.01, the authors Margaret Levine Young and Robert J. Levine still get inquiries about the book and PC-File, the flat-file database program for DOS that was originally released as shareware by Jim Button:
By version 5.01, PC-File was a powerful if quirky database program capable of some multi-file operations (almost like a relational database, but not quite). The program's main disadvantage was its manual, which could most charitably described as sketchy. ... Even in this age of Windows, there are still lots of PC-File users out there.
With Button's permission, they're selling PC-File 5.01 on diskette for $10 plus postage.