This is an announcement for the paper "Unconditional basic sequences in spaces of large density" by Pandelis Dodos, Jordi Lopez Abad and Stevo Todorcevic. Abstract: We study the problem of the existence of unconditional basic sequences in Banach spaces of high density. We show, in particular, the relative consistency with GCH of the statement that every Banach space of density $\aleph_\omega$ contains an unconditional basic sequence. Archive classification: math.FA math.LO Mathematics Subject Classification: 46B03, 03E35 The source file(s), DLT.tex: 74305 bytes, is(are) stored in gzipped form as 0805.1860.gz with size 22kb. The corresponding postcript file has gzipped size 136kb. Submitted from: abad@logique.jussieu.fr The paper may be downloaded from the archive by web browser from URL http://front.math.ucdavis.edu/0805.1860 or http://arXiv.org/abs/0805.1860 or by email in unzipped form by transmitting an empty message with subject line uget 0805.1860 or in gzipped form by using subject line get 0805.1860 to: math@arXiv.org.