In the sentence "although the book was more than 50 years old, it still contained information," the word although is a/an ?

The following question refers to “the philosophy of composition” by edgar allan poe and on writing by stephen king. what is a key difference in the use of details in the texts? poe’s essay is dominated by facts, while king’s memoir is dominated by images and examples. poe references numerous authors and literary works, while king does not reference any other authors or literary works. poe includes a list of all the poems he has written, while king includes a list of all the books he has written. poe’s essay is full of personal details about his wife and children, while king’s memoir is filled with details about his pets.