<human>:  What books would you recommend to understand sustainable energy sources?
<bot>: Some books I would suggest to understand sustainable energy sources are: 
1. Solar Energy: Harnessing the Power of the Sun by Christopher Stewart 
2. Sustainable Energy – Without the Hot Air by David J.C. MacKay 
3. Re-Energizing Our Cities: A Guide to Renewable Energy Solutions for Urban Areas by James E. Accountius 
4. Wind Power – Harnessing Nature's Energy by Jeremy Potter
5. The Solar Revolution: How It Will Change Our World by Chris Goodall.