As my previous attempts to fully learn Bash had been short-living and sporadic I've decided that this time I'm going to fully master it in order to prevent myself from writing one-off scripts on high-level languages to do simple stuff that can be easily lifted by Bash.
This book is a great introduction for those who are real new comers, though I thought of myself as of the same kind.
Turns out that's not the right book for me as it's not focused on particular aspects I'm interested in (networking, IO). However, it's nicely written and it will definitely help if you want to have a high-level view on the most important Bash features.