Both theoretical and experimental results on the behavior of pseudo one-dimensional antiferromagnetic systems are presented. In particular, this report is devoted to a description of the various thermodynamic variables (ξ, χ, χst etc.) of a one-dimensional Heisenberg-like system within the classical spin formalism. The effect of an applied magnetic field and a small interchain coupling are considered. It is demonstrated that the presence of a very small orthorhombic anisotropy has a drastic effect. The results of the calculations are confronted with experimental data on some representative systems.