The intent of this dissertation is to provide a reference guide for any prospective performer of Alec Wilder's four works for marimba: Suite for Solo Guitar (1976), Suite for Trumpet and Marimba (1977), Suite for Flute and Marimba (1977), and Sextet for Marimba and Wind Quintet (1977). The first part of the dissertation provides background information pertaining to Wilder himself, the works for marimba, and theoretical aspects of Wilder's music. The second part addresses specific performance problems contained in the music. The dissertation culminates with the presentation of a performance edition of the marimba part of the previously unedited Sextet. This dissertation will facilitate and enhance future performances of these works. It is hoped that this document will serve to help perpetuate and sustain interest in these important compositions.