This is a full book about Hacking. You need to know assembly and be somewhat comfortable with kernel debuggers and disassemblers. I try to explain everything from scratch except for assembly (because many tutorials about it are already available).
You can find the original posts the book is a compilation of on my site.
Update: The website is down, but all the material is finally available here.
This is a thorough introduction to backpropagation as used in Machine Learning.
This is a tutorial I wrote to solidify my understanding of basic Information Theory and can be used as a thorough and reasoned (i.e. everything is motivated) introduction to Information Theory especially for Machine Learning.
This is a tutorial about Matrix Calculus presenting Magnus and Neudecker's approach to Matrix Differential Calculus.
This is a tutorial about a novel approach to Matrix Calculus using Tensors which intends to be a simplification (at least on a conceptual level) of the approach reviewed in matrixcalculus.pdf.