"How to talk to customers & learn if your business is a good idea when everyone is lying to you."
Wow, what a great book. It ticked all the boxes: it was recommended by friend as a great book, it's short, it's practical, it's insightful, it has good structure, it give you chapter summary and cheatsheet.
This book is essential if you want to learn what your customers what. It's a must for product managers and CEOs.