Book on Beckett and Music by multiple authors. Some good things, some anecdotal material. The idea that Beckett's work is already so perfect that you can't set it to music without destroying it. An analysis of Feldman's "Neither" that loses sight of Beckett for pages at a time.
Book on Celan and music. Based on idea of an antipathy to musicality and distrust of music in Celan's poetry. Mostly set to music in a European context. The book is good, though with too much passive voice for my taste. Musical examples and dense analysis. Has a central thesis.
Book on Shakespeare and music. Too much of a survey; little attention to music itself. Takes a larger view and isn't that helpful methodologically (for me).
Book on Baudelaire and music. Very technical on prosody and song-setting. Musical examples and some dense analysis; charts and drafts. I haven't read enough to know how good it is.
Book on the Spanish Copla and Conchita Piquer. No attention to music or even performance style. An analysis of how the lyrics to the songs may have had a therapeutic affect on listeners during the Franco period. An entire book that's an analysis of a few song lyrics; lyrics not especially complex. This book won a prize from the MLA as best book in Hispanic studies that year.
I haven't found the methodological model for my book, but then it would be my book, wouldn't it? I want to write a book for those that skip over the part of the music book with examples from scores, but still wants to read about music, not about everything except the music.
It could be that the choice of subject makes a certain kind of book inevitable, or not. It is not the same thing seeing Schubert setting Goethe as Fauré setting Baudelaire or Feldman Beckett.