While I was reading the book I noticed some stuff in the text...

Impressive material, this is a very good read! While I read it kind of thorough I also did some minor proofing like fixxing:
* some typeos
* missing eols in bulletlists 
* unification of naming (Varnish with capital 'V' and all varnish-tools with lower case 'v', 
* some text refactorings (very few and gentle).