Think, Act, Be Like Jesus - A Believe Devotional for Kids is a wonderful study/devotional for kids. Written by Randy Frazee, the editor suggests a younger reader, but I feel this book would be ideal and appropriate for children ages 7-12.
This devotional breaks down into three sections: Think - Act - Be. Each devotional is accompanied with a scripture, beautiful illustration and thoughtful discussion.
The book includes a table of contents with various topics and kid relevant issues.
Think, Act, Be Like Jesus is a great way to introduce the importance of daily devotional and biblical study to a child. This could also, be helpful as a family devotion in the evenings.