"The Dark Tower" is an unfinished book that was discovered after Lewis' death. It was written immediately after Out of the Silent Planet and it involves Ransom as well as Lewis (as the narrator). It also introduces MacPhee, a skeptic Scotsman, Orfieu, and Scudamour. The story begins with a discussion about the impossibility of time travel with a physical body. Orfieu claims that since the physical atoms of your body would exist differently, or not at all, in the Othertime, it is impossible for you to physically travel to it. However, he reasons that it is possible to see into this other time, if one has the correct device (like a telescope is used to see long distances).

Orfieu has created such a device, and he unveils it to the group. Through it, they see a time in which a huge Dark Tower is being constructed. They also see a Stingningman (a man with a huge sting on his forehead) who stings a line of people who, after being stung, leave like automatons. They appear to enter the room in a state of awe or worship of the Stingingman. The group spends the next few weeks observing everything they can through the chronoscope. Additionally, they realize that the Tower is an exact replica of a building on campus. They also see a man in the world who is an exact replica of Scudamour. One day the lookalike is transformed into a Stingingman.

The transformation of the lookalike starts to greatly affect Scuadmour. When he sees a woman approaching to be stung, he leaps at the chronoscope. A wild scenes ensues, the ultimate result of which is that the Stingingman and Scudamour switch bodies. The story then transitions to what happened to Scudamour while in the Othertime (which was of course told to Lewis and the others after he returned).

When he arrived, he attempted to convince the woman that he was not going to hurt her. He eventually succeeded. After she left, the White Riders (an enemy we learn little about) attack. They survive the attack, and he makes his way to a library, where he learns that in this time, the people focused all their scientific advances on time, rather than space. As a result, they have known about our time for many years. Scudamour learns the details about their understanding of time. Basically, if one can create a substance of the same exact makeup as that of the Othertime, you can actually bring that other object into this time. It is also part of the theory that time does not travel in a straight line, but in a wave, and can move in either direction. The story ends mid-sentence in the time theory explanation.

"The Man Born Blind" is a short story about a man who was born blind, but given the ability to see later in life. He has a conversation with his wife, asking what light is, and why he can't see it even though everyone else seems to be able to. It upsets him greatly, because he does not think his surgery worked correctly. His wife fails to convince him that it did, or of what exactly she means when she says something is light, or the light is on something.

One morning, while taking a walk, he comes across an artist painting the fog in a cavern below. The artist comments that it is only when the sun hits the fog in the cavern that one can truly see light. Before he knows what is happening, the artist sees the formerly blind man throw himself into the cavern, after the light.

This book also contains "The Shoddy Lands", "Ministering Angels", "Forms of Things Unknown", and "After Ten Years". See my entry on Of Other Worlds for more information on these short stories.