About the book (from Wikipedia):
The Owl and the Nightingale is a twelfth- or thirteenth-century Middle English poem detailing a debate between an owl and a nightingale as overheard by the poem’s narrator. It is the earliest example in Middle English of a literary form known as debate poetry (or verse contest).
There is no certain information about the poem’s author, date of composition or origin…It is equally difficult to establish an exact date when The Owl and the Nightingale was first written. The two surviving manuscripts are thought to be copied from one exemplar, and they are dated to the second half of the 13th century. In ll. 1091-2, the nightingale prays for the soul of “king Henri”, which is thought to reference “either the death of Henry II of England in 1189 or of Henry III of England in 1272”. Scholars see no evidence that the poem predates the surviving manuscripts by many years. It is possible that the poem was written in the 12th or 13th century, and “there is a serious possibility the poem was composed after the death of Henry III in 1272”.
The poem consists entirely of a fierce debate between the eponymous owl and nightingale, as overheard by an unidentified narrator. When he first happens upon them, the Nightingale is perched on a blossom-covered branch, and the Owl is sitting on a bough overgrown with ivy. The Nightingale begins the argument by noting the Owl’s physique, calling her ugly and unclean. The Owl proposes that they proceed civilly and reasonably in their debate, and the Nightingale suggests consulting Nicholas of Guildford, who, although frivolous in his youth, is now a reasonable judge. However, the Nightingale immediately goes on to shame the Owl for the screeches and shrieks she produces, and equates her active time of night with vices and hatred. The Owl in turn posits that the Nightingale’s continuous noise is excessive and boring.