That's why I said it's good companion.

The book covers too much to be thorough. Each chapter gives good introduction to the subject matter and ends with list of suggested reading.

I always read the relevant parts from this book before going deeper. Not everyone is going to dwell into non-euclidean geometry, functional analysis and topology.

Furthermore, I don't think typical self studying engineer in Hacker News wants to learn math using rigorous introduction to analysis. You can get good working knowledge and intuition without knowing what delta epsilon is.