  This paper provides a short introduction to the group testing problem, and
reviews various aspects of its statistical physics formulation. Two main issues
are discussed: the optimal design of pools used in a two-stage testing
experiment, like the one often used in medical or biological applications, and
the inference problem of detecting defective items based on pool diagnosis. The
paper is largely based on: M. M\'ezard and C. Toninelli, arXiv:0706.3104, and
M. M\'ezard and M. Tarzia {\it Phys. Rev. E} {\bf 76}, 041124 (2007).
