Arguably, Riven can be proven to have the most props out of the series.
Riven Descriptive Book
This is a 1950s-era Webster’s Unified Dictionary and Encyclopedia, modified by taking off the gold cover text with solvent, but leaving the shield-and-sprig decor and adding corner accents, and the circular D'ni numeral "5" symbol that is associated with the game, as well as a black rectangle on the first page representing the linking panel. Images from Cyan's Cho Archives also show that prompts for Rand Miller's script were written on pages in the book.
These goggles, that Gehn wears on Age 233, and Atrus wears upon linking into Riven during its destruction, are a pair of Cébé 500 Leather Goggles. Nothing has really been done to them, except for paint on the lenses and leather to represent weathering.
This is a copy of "Omar Khayyam, a Life", by author Harold Lamb, and published by Doubleday, Doran, and Co., Inc. When originally published, the book had a glossy-paper dust cover jacket, but this appears to have not come with the book prop.
The copy used was later embellished for filming with the cover insignia painted in gold, and gold corner accents (oddly with the same D'ni-based numeral "5" in their centers) on both front and back, as well as the two free endpages glued to the cover, to hide the green-patterned cover pages.
On what used to be the title page now holds a blue rectangle of paper, representing the linking panel (again, for later special effects post-production).
Authentic D'ni Linking Book
This is a copy of "Ferment in the Far East, An Historical Interpretation”, written by Mary A. Nourse, published by The Bobbs-Merrill Company, Inc., in 1949. This has been treated in a similar fashion as the Prison Book and the Riven Descriptive Book, where the cover text has been stripped off by solvent, and an insignia and corner accents similar to the Prison book have been painted on. Same as always, there's a blue rectangle for post production on the front page.
Riven Linking Book
This is a copy of "The Pilgrimage Of Faith In The World Of Modern Thought" by Douglas Clyde Macintosh - University of Calcutta 1931