An historical perspective of Theobald Boehm (1794-1881) and his design of the modem alto flute. Chapters I and II discuss the development of design, playing technique and repertoire of the ancestors of the modem alto flute beginning with the Renaissance consorts detailed in the treatises of Agricola, Praetorius and Mersenne, through the Baroqueflate d'amour and its use in the music of J.S. Bach, to Boehm's alto flute design (c. 1855) and its use in early twentieth-century orchestral and chamber repertoire such as Stravinsky's Le Sacre du Printemps (1911), ending with specific aspects of contemporary alto flute design and manufacture since 1950, including the innovations of Dutch flutemaker Eva Kingma. Chapters III and IV concentrate on Boehm's mechanical and acoustical developments for the concert flute in C, the resulting modem alto flute in G, and his career as a virtuoso flutist, teacher, and composer. Chapter V is a critical commentary on Boehm's arrangement of Beethoven's Largo from the Concerto for Piano, Op. 15, No. 1 for alto flute and piano (c. 1858). Appendices A and B include the facsimile of the unpublished Largo manuscript and a list of Boehm's works for alto flute.