I have been following Kristina for a long time, and 20000 Leagues Under the Sea was one of her first readers that I read. It definitely helped with both reading ability and learning new vocabulary. Words, phrases, and idioms which might be new to the reader are denoted in bold type and the definition/explanation is just below the text. Very handy! Listening skills are also improved by listening as you read. The combination of aural and visual presentation definitely helps me to comprehend and retain what I am studying. You can’t go wrong with any of Kristina’s Russian Readers. I highly recommend them.