If you aim to find an educational app for preschool and primary school children in App Store, you will be unpleasantly surprised. There are just an insignificant number of them (not counting games)! These are mainly coloring books, but there are practically no books in Russian. But it seems that the developers from Blue Marlin Technologies decided to change the situation. They released a great program called KidBook! The app is free and very high quality. Even adults will be interested in remembering the past, leafing through familiar works, and even children will be completely delighted. When we first open the program, we find ourselves in a store where we are offered to download works. So far there are only three of them, but let's hope for a quick update of the assortment. Here, you can set restrictions on the purchase and removal of content. And it's nice, because you don't have to go into the basic settings iPad. 
Next, we move on to choosing a book. Everything is simple here. The only thing I didn't really like was the loading time of the book. You will have to wait 30-40 seconds. It seems not long, but annoying. I think the authors of the program will optimize this over time. 
The books themselves are great. Professionally rendered and voiced, intuitive. 
But most importantly, they are interactive! The child will take a direct part in the adventures of the heroes. It naturally rains, leaves fall, and by clicking on the screen you can revive the pictures! 
Also, at the moment, the store has a wonderful alphabet. It is paid, but it costs mere pennies. Moreover, having bought it, you can support the further development of the project. 
Well, let's summarize. We have a solid application for children in all respects. Let me remind you that there are practically no analogues in App Store. Russian language support and interactivity add brilliance. Well, all the developers have to do is wish them not to be satisfied with what has already been achieved and to please our children with new books!
