This document describes the Millimeter Anisotropy eXperiment IMaging Array ( \maxima ) , a balloon-borne experiment measuring the temperature anisotropy of the Cosmic Microwave Background ( CMB ) on angular scales of 10 \mins to 5 \dega . \maxima data are used to discriminate between cosmological models and to determine cosmological parameters . \maxima maps the CMB using 16 bolometric detectors observing in spectral bands centered at 150 GHz , 230 GHz , and 410 GHz , with 10 \mins resolution at all frequencies . The combined receiver sensitivity to CMB anisotropy is \sima 40 \micro K \sqrt { sec } , the best reported by any CMB experiment . Systematic errors are rejected by using four uncorrelated spatial modulations , multiple independent CMB observations , heavily baffled optics , and strong spectral discrimination . Observation patterns are well cross-linked and optimized for the extraction of cosmological information . Pointing is reconstructed to an accuracy of 1 \mina . Absolute calibration uncertainty of 3-4 % is the best achieved by any sub-orbital CMB experiment . Two \maxima flights were launched from the National Scientific Balloon Facility in Palestine Texas in 1998 and 1999 . During a total of 8.5 hours of CMB observations , 300 deg ^ { 2 } of the sky were mapped , with \sima 50 deg ^ { 2 } overlap between the two flights . The observed region was selected for low foreground emission and post-flight data analysis confirms that foreground contamination is negligible . Cosmological results are presented from the 1998 flight , \maximai , in which 122 deg ^ { 2 } of sky were mapped over 3 hours . A maximum likelihood map with 3 \mins pixelization is obtained from the three most sensitive and best tested detectors . The angular power spectrum derived from this map shows a narrow peak near \ell = 200 , and is consistent with inflationary Big Bang models . Within these models , cosmological parameters are estimated , including total density \Omega _ { tot } = 0.9 _ { -0.16 } ^ { +0.18 } , baryon density \Omega _ { b } h ^ { 2 } = 0.033 \pm 0.013 , and power spectrum normalization C _ { 10 } = 690 _ { -125 } ^ { +200 } \mu K ^ { 2 } . In combination with recent supernova observations , we obtain additional constrains on the matter density \Omega _ { m } = 0.32 { +0.14 \atop - 0.11 } and the dark energy density \Omega _ { \Lambda } = 0.65 { +0.15 \atop - 0.16 } . All parameter estimates are presented at 95 % confidence . The final chapter is a discussion CMB polarization anisotropy , including an overview of \maxipol , the polarization sensitive follow-up to \maxima . Measurements of CMB polarization are an essential complement to those of temperature anisotropy . \abstractsignature