German music theorist and composer whose Syntagma musicum (1614–20) is a principal source for knowledge of 17th-century music and whose settings of Lutheran chorales are important examples of early 17th-century religious music.

He studied at Frankfurt an der Oder and was organist and eventually court kapellmeister to Duke Heinrich Julius of Brunswick-Wolfenbüttel. After his patron's death in 1613, Praetorius spent more than two years at Dresden, where he heard the latest Italian music. In his last years he visited many German courts, as a director, performer, and consultant. Zealous for the advancement of music, he admired Italian music and had a predilection for rich and varied settings for voices and instruments. His output was considerable and varied. The most significant collections of his works are Musae Sioniae (nine parts, 1605–10), consisting of more than 1,200 settings of chorales, partly for 8 to 12 voices in Venetian double choir style, partly in simple two-, three-, and four-part style; and the Puericinium (1621), where the chorale strophes receive varied treatment, foreshadowing the chorale cantata. Praetorius published much music other than his own, and in his collection Terpsichore (1612) he introduced several hundred foreign dance pieces to Germany.

Of the three surviving parts of the Syntagma musicum, the most important is Vol. II, which describes and classifies many ancient and all existing musical instruments. They are lavishly illustrated in an appendix.