The quantum statistical behavior of a small collection of N two-state atoms strongly coupled to the field of a high-finesse optical cavity is investigated. Input-output characteristics are recorded over the range 3 less-than-or-similar-to N less-than-or-similar-to 65, with bistability observed for N greater-than-or-similar-to 15 intracavity atoms and for a saturation photon number n0 congruent-to 0.8. For weak excitation the transmitted field exhibits photon antibunching as a nonclassical manifestation of state reduction and quantum interference with the magnitude of the nonclassical effects largely independent of N.