The User Experience Team of One

This is my #1 recommended book for anyone who is a solo consultant, esp working with startups or consultancy where you're dealing with lots of different projects/clients. It's one of the few books on ux that covers the widest range of miracles you will perform as a solo uxer. No BS - this book is both practical (gives you step by step how tos) and tactical (helps you understand the why's). This is the one book I constantly picked up over and over and over again earlier on in my career whenever I needed inspiration, needed a reminder about how to do something, or was unsure and needed a plan to tackle a problem fast.