The Prapañcasāra by Śrī Śaṅkara is devoted to the science of mantras, also known as Mantraśāstra. There are several published editions including commentaries, elaborating on the subject of the science of mantras. Supposedly, Śaṅkara composed this work as a summary of an older and vaster compendium of Tantra.
First, the commentary by his Śaṅkara’s disciple, Padmapādācārya (8th century) including a sub-commentary. The elaborate introduction is available in English on archive.org and includes a summary of all chapters.
Another edition includes the commentary called Prapañcasārasāra Saṅgraha (16th or 17the century). From the preface:
In this volume we publish the work entitled Prapañchasārasāra Saṅgraha of Geervanendra Saraswathi. It is fairly a big work consisting of 15,000 granthas, and hence we are publishing it in two Parts. Sri Sankara, the great Philosopher wrote Prapanchasara, a work on Mantra Sastra. The present work is an elaboration of the subject of Prapanchasara and hence is styled Prapanchasarasara Sangraha.
Another work on Mantraśāstra is the Śāradātilaka-tantra: composed, probably in the twelfth century, by Lakṣmaṇadeśika (source). It is available on archive.org in Sanskrit (includes commentaries, 1000+ pages) and a translation of the 25th chapter is posted on acamedia. An English translation of the root text is also available under ISBN 8170301750.
Mantra Śāstra is common to all the traditions including Śāktā, Vaiśnava, Śaiva, Śrauta and Bauddha. (source) The texts suchs as Mantramahodadhi and Mantramahārṇava are mentioned as well.
For more literature regarding Mantraśāstra, see chapter VII of “A history of Indian Literature” Volume 2.