These proceedings contain 68 papers from November 1999 conference, covering a wide range of areas in language acquisition and language development. The volumes include the keynote paper by Elissa Newport and Richard Aslin, and the plenary paper by Stephen Crain. The table of contents and other details can be found on our web site at: http://www.cascadilla.com/bucld.html or you can send a blank e-mail to bucld24@cascadilla.com to have the order form and table of contents automatically sent to you by e-mail.