Charles, R. H. A Critical and Exegetical Commentary on the Revelation of St. John: With Introduction, Notes, and Indices, Also the Greek Text and English Translation. The International Critical Commentary. 1920. Reprint. Edinburgh: T. & T. Clark, 1985.
Charles’ commentary is generally highly valued, in particular for its philological information as well as its analyses of the relationship between Revelation and other ancient literature.
His literary-critical reconstructions, however, are quite arbitrary. Charles is often cited for his dictum that John wrote in Greek, but thought in Hebrew.
Parts of this commentary are now available online.