%0 Journal Article %T The ideal envelope of an operator algebra %A David P. Blecher %A Masayoshi Kaneda %J Mathematics %D 2001 %I arXiv %X A left ideal of any C*-algebra is an example of an operator algebra with a right contractive approximate identity (r.c.a.i.). Conversely, we show here and in a `pre-quel' to this paper [B], that operator algebras with r.c.a.i. should be studied in terms of a certain left ideal of a C*-algebra. We study operator algebras and their multiplier algebras from the perspective of `Hamana theory' and using the multiplier algebras introduced by the first author. %U http://arxiv.org/abs/math/0111122v1