Collision Earth! The threat from outer space by Peter Grego (Ward Lock, 1998) £10.99.
Accessible source of information about past impacts and the search for future threats.

Fire on Earth: In search of the Doomsday asteroid by John and Mary Gribbin (Pocket Books, 1996) £6.99.
Readable account of where comets and asteroids originate and their relationship with the planets.

Meteorites by Robert Hutchison and Andrew Graham (Natural History Museum/HMSO, 1994) £6.95.
Good, basic introduction to different types of meteorites, with plenty of pictures.

Meteorites and their Parent Planets by Harry Y McSween (Cambridge University Press, 1999) £16.95.
Comprehensive, anecdotal analysis of what meteorites tell us about the beginning of the world.

Rocks from Space by O Richard Norton (Mountain Press, 1998) $30.
Reader-friendly guide for meteorite hunters, with details about famous finds and significant events.

Rogue Asteroids and Doomsday Comets by Duncan Steel (Wiley, 1995) £19.99.
Examination of the threat to humankind from space rocks, written by an astronomer at the Anglo-Australian Laboratory.

Websites

Meteorite Central
www7.pair.com/arthur/meteor/index.shtml
General meteorite news, chat and links for anoraks.

On the question of the Mars meteorite
www.lpi.usra.edu/lpi/meteorites/mars_meteorite.html
Lunar and Planetary Institute site with detailed analysis of Mars meteorite ALH84001.

Sahara meteorite prospecting
www.saharamet.com
Information on how to search for meteorites in the Sahara desert.

ANSMET: The Antarctic search for meteorites
http://geology.cwru.edu/~ansmet/
Part of the (US) Case Western Reserve University site, with good pictures of the scientists' discoveries on the ice.

Asteroid and comet impact hazards
http://impact.arc.nasa.gov/
Excellent NASA site on its view of the impact threat to Earth, including a list of potentially hazardous asteroids.

The Spacewatch Project
pirlwww.lpl.arizona.edu/spacewatch
Documents the work of the University of Arizona's Spacewatch programme, which scans the sky for passing asteroids and comets.

Societies

British Astronomical Association
Burlington House
Piccadilly
London W1J 0DU
Tel: 020 7734 4145
Website: www.britastro.org
Full membership is £40.50 a year, including the BAA journal.

Society for Popular Astronomy
SPA Secretary
36 Fairway
Keyworth
Nottingham NG12 5DU
Website: www.popastro.com/home.htm
Membership is £16 a year, including quarterly magazine Popular Astronomy.

Spaceguard UK
The Spaceguard Centre
Llanshay Lane
Knighton
Powys LD7 1LW
Website: www.spaceguarduk.com
British arm of a global scientific search for near-earth objects. General membership is £12 a year for anyone who is interested and has relevant skills to offer.

The Meteoritical Society
Website: www.meteoriticalsociety.org
US-based international organisation. Membership is $110 (£55) a year, including the journal Meteoritics and Planetary Science, which in turn publishes an annual Meteoritical Bulletin listing new finds.

Films

Meteor (US, 1979) Directed by Ronald Neame
The United States and the Soviet Union join nuclear forces as a giant asteroid heads Earthward and the rock is blasted into dangerous pieces. Sean Connery plays an American scientist, Natalie Wood a Russian interpreter.

Deep Impact (US, 1998) Directed by Mimi Leder
Follows the lives of a panicky bunch of Americans as astronauts (led by Robert Duvall) try to divert or destroy a 'comet' that threatens humankind with mass extinction.

Armageddon (US, 1998) Directed by Michael Bay
Testosterone-fuelled box-office competitor to Deep Impact, with Bruce Willis and Ben Affleck heading the team of deep-core drillers sent to nuke a Texas-sized asteroid that is due to strike Earth in 18 days' time.