One of them, " Tres Comedias" ( by one J. Benavente, born 1866) was previously owned by Dorothy Dudgeon .. I'm guessing that it was a good while ago, as the name is written with a fountain pen and Dorothy is not a common name these days.
Here's what the web has to say about it ... there are 3 plays, "Sin Querer", "De Pequeñas causas" and "Los intereses creados" ...
The text of this edition is taken from Benavente's Teatro, Librería delos Sucesores de Hernando, Madrid
Los intereses creados is chosen as one of the finest of Benavente's plays, and the one best suited to class use; the two shorter pieces are included to give an idea of the author's more normal manner. Although De pequeñas causas... was produced on the stage after Los intereses creados, it precedes it in this edition in order that the long play may stand at the end of the volume. It is believed that these plays can be read to greatest advantage after students have had one year of Spanish. The Notes and Vocabulary have been prepared with that in mind, as much material as possible being placed in the Vocabulary rather than in the Notes. However, in the present dearth of good elementary texts, the book might be used toward the end of the first year...
As you can see, they seem very concerned about "suitability" ... I get the idea that they are more worried about "content" rather than vocabulary! That is, no dubious subject matter ...after all, the copy I got was dated 1941, not exactly in modern times.
Here's Mecano with "Aire" .....
Una noche de resaca al tratar de despertar
note que por el ombligo me empezaba a desinflar
que mi cuerpo se arrugaba como un papel vegetal
e iba pasando, que curioso, al estado gaseoso.
y tras la metamorfosis me senti mucho mejor
era un aire gris oscuro y con bastante polucion
se notaba en cualquler caso que era aire de ciudad
que si bien no es el mas sano. lo prefiere el ser humano.
Aire, soñe por un momento que era aire
aire. oxigeno. nitrogeno y argón
sin forma definida ni color
fui aire volador.
como yo soy muy consciente hasta en esta situacion
decidi ser consecuente con mi nueva dimension
y probe a ser respirado por la que duerme a mi lado
sin entrar en pormenores yo se hacer cosas mejores.
como no me satisfizo la experiencia sexual
se me inflaron los vapores. me converti en huracan
di unas tres o cuatro vueltas y a la quinta me canse
este cuarto es muy pequeño para las cosas que sueño.
Aire. soñe por un momento que era aire
aire. oxigeno, nitrogeno y argón
sin forma definida ni color
fui aire volador.
Y lo siento por mi novia y el cristal que me cargue
me escape por la ventana y en picado me lance
pero tuve mala suerte y cuando iba a remontar
me volvi otra vez humano. no falteis al funeral.
Aire, soñe por un momento que era aire
aire. oxigeno, nitrogeno y argón
sin forma definida ni color
fui aire volador.