Essential perhaps if you want to do research in Machine learning or work on developing new machine learning algorithms and libraries. Hardly essential if all you want to do is take a well understood algorithm from a well known ML package and apply it your data. What is essential then is knowing the relative strength and weaknesses of the different existing approaches and knowing which one to pick given your data and computational limitations. And as far as I can tell non of those books cover that.<p>That being said, the list is excellent for people who want a solid theoretical grounding of the underlying mathematics, and many of my favorite books are on the list.