Direct ion counting using a tandem accelerator mass spectrometer permits ±2% dating of a 1 mg sample of carbon in an hour's time. How the tandem accelerator mass spectrometer works is described at length. Target preparation procedure is reviewed. Examples illustrate the type of information that can be derived from this procedure including dating and what materials may lead to false inferences. The precision of the technique is dependent upon ion production; this aspect is being improved. A beryllium isotope ¹⁰Be can be used to fingerprint ceramics for provenance studies. -- AATA