What makes a good technical book 'good'?

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I have an unenviable target of reading at least one technical book a month. I have enjoyed reading dozens of them. Here's what I think are the ingredients of the secret sauce that makes technical books great -

1. They are written in plain-English
2. They have a no-fluff, straight-forward tone & a conversational style
3. They identify the audience in the beginning & meet the expectations they set
4. They have some kind of takeaways you can benefit from - practical examples, re-usable code samples.
5. Their content is well-organized & structured.
6. Attention is paid to technical accuracy, grammar, layout & fonts used
7. Illustrations, backgrounders & infoboxes are provided where required & important information is highlighted.