Conservative Judaism's theological evolution has proven notoriously difficult to define through traditional ideological statements, yet its contemporary prayer book, Siddur Sim Shalom, offers revealing insights into the movement's developing religious worldview. Through careful analysis of Hebrew texts, English translations, and supplementary materials - compared against earlier Conservative prayer books and traditional liturgy - several key theological shifts emerge: an embrace of pluralism through multiple prayer versions, a doctrine of progressive revelation enabling liturgical innovation, and a transition from sacrificial worship toward ethical imperatives of peace and social justice. The prayer book demonstrates enhanced status for women through inclusive language and ritual participation, reframes Israel's election as conditional responsibility rather than absolute chosenness, and reconceptualizes mitzvot as divinely "given" rather than "commanded." Mystical and Hasidic influences appear throughout, while the overall theological framework reflects Abraham Joshua Heschel's ethical mysticism and Mordecai Kaplan's reconstructionist philosophy. This liturgical analysis reveals how Conservative Judaism has crafted a centrist theology emphasizing ethical living, individual spiritual autonomy, and adaptive tradition while maintaining ties to historical Jewish practice, providing concrete evidence of the movement's theological development and offering a methodological model for understanding religious movements through their prayer books.