We report the first observation of single top quark production
using 3.2 fb-1 of p anti-p collision data with s**(1/2) ñ.96 TeV
collected by the Collider Detector at Fermilab. The significance of the
observed data is 5.0 standard deviations, and the expected sensitivity
is in excess of 5.9 standard deviations. We measure a cross section of
2.3+0.6_-0.5(stat + syst) pb, extract the CKM matrix element value |V(tb)|
0.91+0.11_-0.11(stat + syst) +/- 0.07 (theory), and set the limit |V(tb)|
> 0.71 at the 95% C.L.