The existence of lensed quasars with splitting angles larger than 7 has been predicted on the basis of the cold dark matter model. We searched for these large-separation lensed quasars from the spectroscopically classified ∼ 40, 000 quasars obtained by the Sloan Digital Sky Survey (SDSS), and succeeded in discovering the first lensed quasar by a cluster of galaxies, SDSS J1004+4112: It consists of four images, and the maximum separation is 14.62 . Here we describe the discovery and the

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... observations of this system, as well as the latest results of the large-separation lens search in the SDSS. We also present the new statistical model which fully incorporates non-sphericity of dark halos, and compare the theoretical predictions with the SDSS results.