Like many short stories, books, TV and radio dramas from the late 40s (1947/48) This story deals with a group of space travelers looking for a new world to settle on. What sets this one apart a bit, it the world they are leave has been destroyed by a nuclear war, but by an environmental disaster. The sun is too hot, and the water is evaporating too quickly.

There isn't much known at the start about the space travelers, other then they are looking for a new world, have a some what high moral compass (at least when it comes to their own race). And have made some advancements in weapons technology. We find out they avoided total destruction using advanced weapons, but are never told if this is because of the moral high ground, or if the environmental disaster was such a threat everyone worked to solve it.

In the end very little is learned about the environmental disaster, other then they needed to leave the planet. Our space travels, do find a planet that is suitable for life. In fact, it has life on it at least from what they can find, small animal life. At one time there were great cities, but they can't find an intelligent life. Of course they start to explore, and start to learn more about what happened.
Someone finds an old library, or maybe a class room (at very least a large deposit of books). And sooner rather then later, they learn how to read the books. Mean while, the commander is getting ready to send a report back home - telling them he found a planet.
Someone from one of the exploring parties reports that they found fresh foot prints, and from the looks of things - they are bi-peds - and maybe intelligent.
They finally concluded there aren't many left, and it shouldn't be a problem when more of the space travelers ships arrive. While in the library, they are attacked by someone using a projectile weapon (primitive). And the small fight is quickly stopped. The member of the group finds a key to reading the books - and announces, what they just killed was called "man".

Thou the story never comes right out and says man destroyed itself with nuclear weapons - it is heavily implied.

The story never resolves if more of the alien race do come to settle, nor the environmental issues they faced.

Like a lot of stories from this time period - nuclear destruction was heavy on peoples minds, stories were used as warnings. I'm not sure this story achieved that level thou.

Over all it's a good story that I've heard dozens of times on old radio dramas like x-minus one, and have seen in old tv programs like Twilight Zone and Outer Limits.

This had a lot of potential thou to capture two different issued that we still potentially face today.
It was a good story, but not great. And because these types of stories have been told over and over again - it was fairly predictable.