Im an avid reader of science papers concerning space flight and possible isssues arising from developing the technology
Interstellar Travel and Multi-Generation Spaceships. edvYoji Kondo (Apogee Books 2003) This includes a new study on the size of viable human populations.
Centauri Dreams by Paul Gilster (Copernicus Books 2004) Recent review of interstellar technologies
Classical and Quantum Gravity by Miguel Alcubierre (vol 11, L73- L77 1994) Development of warp drive technology.
Classical and Quantum Gravity also provide interesting papers on reducing energy requirements for warp bubbles and optical effects for warp fields.
You never know we might have Starships in100 years