The Browning Cyclopædia. Edward Berdoe, Macmillan, 1902. Elaborate analysis of each poem. Many textual notes. Interpretations often involved and far-fetched to the point of being untenable.
[Handbook of Robert Browning's Works]. Mrs. A. Sutherland Orr. First edition, 1885; sixth edition, 1891. Republished by Bell and Sons, London, 1902. Explanatory analysis of each poem. Edition of 1902 contains complete bibliography of Browning's works. Written at the request of the London Browning Society.
For criticism see, as books varying widely in point of view and scope, but each of distinct interest:
[An Introduction to the Study of Robert Browning's Poetry]. Hiram Corson. Boston, 1886.
[An Introduction to the Study of Browning]. Arthur Symons. London, Cassell and Company, 1886.
[Life of Robert Browning]. William Sharp. Walter Scott and Company, London, 1897.
[The Poetry of Robert Browning]. Stopford A. Brooke. Crowell and Company, 1902.
[Robert Browning]. G. K. Chesterton. Macmillan, 1903.
[Robert Browning]. C. H. Herford. Dodd, Mead and Company, 1905.
Interpretations of Poetry and Religion, by George Santayana, Scribners, 1900, contains an interesting presentation of Browning's work in a chapter entitled "The Poetry of Barbarism."