The human future in space
Lighting the path : solar sails and interstellar travel
Sailcraft in turbulent political and technical waters
The planetary society and solar sailing
Interstellar precursors and the 100 Year StarshipTM
A mission to the solar gravitational lens focus
Extending human presence, not humans
Creating a multi-planet species : humans to Mars
Implications and conclusions
Appendix : a human Mars mission.