Hello,
Python for Scientists and Engineers was the first book I wrote, and the one I still get queries about. It had been out of print for more than a year, but I could never get myself to update it, because it looked like too much work.
Recently, I asked for help in updating it, and a few people volunteered. Thanks to these volunteers, the book is now free to read online (and will remain so).
The book assumes you already know Python, or any other language. I feel there are too many resources for beginners, and not enough for intermediate/advanced programmers.
Anyway, check it out here:
http://pythonforengineers.com/python-for-scientists-and-engineers/
Cheers, Shantnu