  By high temperature series expansion, exact diagonalisation and temperature
density-matrix renormalisation the magnetic susceptibility $\chi(T)$ and the
specific heat $C(T)$ of dimerised and frustrated $S=1/2$ chains are computed.
All three methods yield reliable results, in particular for not too small
temperatures or not too small gaps. The series expansion results are provided
in the form of polynomials allowing very fast and convenient fits in data
analysis using algebraic programmes. We discuss the difficulty to extract more
than two coupling constants from the temperature dependence of $\chi(T)$.
