Superfluid helium-3 is one of the most exotic and most inaccessible materials on Earth. It is also one of the most interesting - albeit, at least for present technological applications, also seemingly one of the most useless.
Bibliographic note
Review of "The Superfluid Phases of Helium-3 by D. Vollhardt and P. Wolfle, Taylor and Francis, 619pp, ISBN 0 85066 4128.
