Keepers of the Razor: Current Descendants of the Inner Circle.
This book has some useful information if you're doing the Daedric quest to restore Mehrune's Razor. If you're not doing this quest, however, the book isn't worth the time to read. It really is just a list of non-player characters in possession of the various fragments of the weapon. The text does not stand alone.
Killing--Before You're Killed, by Eduardo Corvus.
Some game-related battle tactics for melee fighting. Nothing but contempt is given with regards to magic, and nothing whatsoever is given with regards to archery. The advice on using bladed weapons is applicable within the game-world, but probably not in real life. This is the kind of book you open so you can collect the skill point, but you gain little from the actual reading of it.
A Kiss, Sweet Mother.
Another quest-related tome, this time for the Dark Brotherhood quest. This very brief text instructs the reader on the sacrificial ritual for summoning the Dark Brotherhood. It is creepy, but offers little substance.
The Knights of the Nine, by Karoline of Solitude.
This book can be summarized as, "The Knights of the Nine were awesome. Then they fell from grace and weren't awesome anymore. Then everyone forgot about them." What the book lacks is any particular description of what the Knights of the Nine actually did in order to be held in high regard during their heyday. In other words, the author never explained why the reader should care about the Knights.
Kolb & the Dragon: An Adventure for Nord Boys.
It's a choose-your-own-adventure-style book! Each page sets the scene, with a list of different pages you could turn to next depending on the choice you make. I loved this style of interactive adventure tale when I was a kid, so reading this book was like having a huge corner slice of birthday cake with extra buttercream frosting. The epub version doesn't work so well, even though the compiler was careful to preserve page numbers. However, reading this book in-game was delightful. I had to go through it multiple times, choosing different paths so I could see all the endings. It's a very short and simple tale, of course, but that doesn't lessen the delight. Props to the game developers for even thinking to include a book like this.
Note: I am not connected to Bethesda in any way, and no one asked me to do these reviews. I am doing this purely for my own fun, as time allows. I don't have an agenda, other than the joy of reading and writing. If I panned your favorite Skyrim book, sorry. If I gave five stars to one you thought was awful, also sorry. These are my opinions and mine alone. You're entitled to your own.