When my son was learning to read, it seemed we couldn’t get our hands on enough easy readers to keep him interested and challeneged. He finished the Bob Books and then we needed something else that was leveled, but that kept his interest as well. One of the sets of readers that we enjoyed the most was the DK Readers. Also known as Dorling Kindersley Readers or Eyewitness Readers. If you are familiar with other DK books, or DK Eyewitness books, you can immediately picture their style. Glossy pages with many real photographs on each page. The DK Readers are leveled, which means you can start at the lower levels with beginning readers, and as they improve, you can easily pick books from higher numbers. One thing to keep in mind though, is that every company that makes leveled readers has their own definition of level 1 or 2. So DK Readers level 2 may actually be the same reading level as Step-into-Reading Readers level 3.
These DK readers are non-fiction, but written in a way that is engaging so it’s not like reading a textbook. For instance, one that my son enjoyed was Fire Fighter! 
This one follows a specific firefighter throughout her day and explains the job from staying at the firestation to heading out on a fire call. What I appreciated was that the text was at a level my son could read, but then most pages have a little extra box of text to explain a tool or fact. The box is written at a bit higher reading level, so a parent can read those parts or kid can challenge himself.
The books also have a simple index which became another teaching tool. Kids can find words they recognize from the reading and learn how to find them within the book. There are many different topics to choose from, and there is even a Star Wars Readers subset if you have a kid that’s into that. These books are also small paperbacks but sturdy to hold up to wear and tear. They are cheap as well, usually around $3.99 new. But you can find them used for, just a few cents, and at your library as well.
To see a complete list of the DK Readers, check out DK’s website list directly.
Cloudy with a Chance of Books 