Vsevolod Dyomkin. Lisp Hackers. Interviews with 100x More Productive Programmers.

Fantastic book. Can be found online at http://leanpub.com/lisphackers. It is a collection of interviews with 14 developers who use Lisp in real life.
After reading this book I have a new look into Lisp. I need to look at it more closely. :-)
It's disadvantages:

1. lack of static typing
2. difficult to work with in a big projects code bases (around 500 kloc)

Advantages:

1. DSL support
2. protocols
3. ability to run partial programs
4. Having fun
5. extend your mind 
6. can be used in projects where customer doesn't care about the tools but getting job done.

Productivity tips:

1. Start from minimal running code and move forward in a long series of very small steps.
2. Learn new languages  to meet new people, to think in a new way.