(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) We present a measurement of eta meson production in photon-photon interactions produced by electron-positron beams colliding with ... GeV. The measurement is done with the KLOE detector at the -factory DAPhiNE with an integrated luminosity of 0.24 fb^sup -1^. The e ^sup +^ e ^sup -^ arrow right e ^sup +^ e ^sup -^ eta cross section is measured without detecting the out-going electron and positron, selecting the decays eta arrow right pi ^sup +^ pi ^sup -^ pi ^sup 0^ and eta arrow right pi ^sup 0^ pi ^sup 0^ pi ^sup 0^. The most relevant background is due to e ^sup +^ e ^sup -^ arrow right etaγ when the monochromatic photon escapes detection. The cross section for this process is measured as sigma(e ^sup +^ e ^sup -^ arrow right etaγ) = (856±8^sub stat^±16^sub syst^) pb. The combined result for the e ^sup +^ e ^sup -^ arrow right e ^sup +^ e ^sup -^ eta cross section is sigma(e ^sup +^ e ^sup -^ arrow right e ^sup +^ e ^sup -^ eta) = (32.72±1.27^sub stat^±0.70^sub syst^) pb. From this we derive the partial width Gamma(eta arrow right γγ) = (520±20^sub stat^±13^sub syst^) eV. This is in agreement with the world average and is the most precise measurement to date.