The Thirty Short Chorale Preludes op. 135a were first published in 1915 by N. Simrock-Verlag. Any trace of the engraver’s manuscript owned by the publisher’s family was lost in 1929 with the disbanding of the company. It only resurfaced in 2019 in the Archive of the Prague Conservatory. It has therefore been possible to use Reger’s autograph as a second primary source in preparing this revision of the musical text of the Reger Complete Edition.