These papers give an introduction into the field for non-specialists:

About ultralow temperatures
W. Ketterle:
How are temperatures close to absolute zero achieved and measured?
Scientific American.com, Ask the Experts, January 19, 2004.
http://www.sciam.com/askexpert_question.cfm?articleID=00037290-04B2-1007-84B283414B7F0000&pageNumber=1&catID=3
Scientific American, May 2004, p. 120.

Talk on quantum statistics and BEC
Wolfgang Ketterle:
Bose-Einstein Condensation: Identity Crisis for Indistinguishable Particles.
in “Quantum Mechanics at the Crossroads”, eds. James Evans and Alan S. Thorndike, Springer, Berlin , 2006), pp. 159-183.
Link

Nobel Lecture
W. Ketterle:
When atoms behave as waves:  Bose-Einstein condensation and the atom laser.
in: Les Prix Nobel 2001 (The Nobel Foundation, Stockholm, 2002), pp. 118-154.
reprinted in: ChemPhysChem 3, 736-753 (2002).
Rev. Mod. Phys. 74, 1131-1151 (2002).
Link

Nature Insight Review
J.R. Anglin and W. Ketterle:
Bose-Einstein condensation of atomic gases.
Nature 416, 211-218 (2002).
Paper (pdf, 1.6 MB)

Popular summary on atom amplification and vortex generation in Bose-Einstein condensates
W. Ketterle
The Magic of Matter Waves
physics@MIT, Departmental Newsletter 2001
Paper (pdf, 285 kB)

Illustrated introduction and early experiments
D.S. Durfee and W. Ketterle:
Experimental studies of Bose-Einstein condensation.
Optics Express 2, 299-313 (1998).
Paper (pdf, 1023 kB)

Feature paper in Physics Today
W. Ketterle:
Experimental studies of Bose-Einstein condensation.
Physics Today, December 1999, pp. 30-35.
Preprint (pdf, 867kB)

"Encyclopedic definition" of Bose-Einstein condensation
W. Ketterle:
Bose-Einstein condensation.
McGraw-Hill Encyclopedia of Science & Technology, 9th Edition, in print.
Preprint (pdf, 594 kB)see also Introdution to BEC

"Encyclopedic definition" of the atom laser
W. Ketterle:
Atom laser.
McGraw-Hill 1999 Yearbook of Science & Technology (McGraw-Hill, New York, 1998), pp. 43-46.
Preprint (pdf, 258 kB)see also The MIT Atom Laser

For further popular papers, see the List of Publications (pdf, 114 kB)