Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great introduction to nonparametric estimation.

This book is a nonparametric introduction written for social sciences students. This implies that it's light on the mathmetical side. But the nonparametrics are easy to understand anyway. This is a highly recommended book for those who want to formalize their thoughts and want to test that model with real life data but find it difficult to apply classical parametric methods.