  We describe calculations of the properties of quantum fluids inside nanotubes
of various sizes. Very small radius ($R$) pores confine the gases to a line, so
that a one-dimensional (1D) approximation is applicable; the low temperature
behavior of 1D $^4$He is discussed. Somewhat larger pores permit the particles
to move off axis, resulting eventually in a transition to a cylindrical shell
phase--a thin film near the tube wall; we explored this behavior for H$_2$. At
even larger $R\sim 1$ nm, both the shell phase and an axial phase are present.
Results showing strong binding of cylindrical liquids $^4$He and $^3$He are
discussed.
