 Many composers and theorists of the 16th, 17th, and 18th centuries wrote "how-to guides" for chord-playing musicians, to aid them in realizing figured bass notation, including Gregor Aichinger, Filippo Bonaffino, Friedrich Erhard Niedt, Jean-Philippe Rameau, Georg Philipp Telemann, C. P. E. Bach, and Michael Praetorius.In the 20th and 21st century, figured bass is also sometimes used by classical musicians as a shorthand way of indicating chords when a composer is sketching out ideas for a new piece or when a music student is analyzing the harmony of a notated piece of music (e.g., a Bach chorale or a Chopin piano prelude).Figured bass is not generally used in modern musical compositions, except for neo-Baroque pieces.