We have conducted a high-resolution imaging study of the Taurus-Auriga star-forming region in order to characterize the primordial outcome of multiple star formation and the extent of the brown dwarf desert . Our survey identified 16 new binary companions to primary stars with masses of 0.25-2.5 M _ { \sun } , raising the total number of binary pairs ( including components of high-order multiples ) with separations of 3–5000 AU to 90 . We find that \sim 2/3–3/4 of all Taurus members are multiple systems of two or more stars , while the other \sim 1/4–1/3 appear to have formed as single stars ; the distribution of high-order multiplicity suggests that fragmentation into a wide binary has no impact on the subsequent probability that either component will fragment again . The separation distribution for solar-type stars ( 0.7–2.5 M _ { \sun } ) is nearly log-flat over separations of 3–5000 AU , but lower-mass stars ( 0.25–0.7 M _ { \sun } ) show a paucity of binary companions with separations of \gtrsim 200 AU . Across this full mass range , companion masses are well described with a linear-flat function ; all system mass ratios ( q = M _ { B } / M _ { A } ) are equally probable , apparently including substellar companions . Our results are broadly consistent with the two expected modes of binary formation ( freefall fragmentation on large scales and disk fragmentation on small scales ) , but the distributions provide some clues as to the epochs at which the companions are likely to form .