A very strange artefact. It is, basically, the diary of the TA on a course taught by Pólya and Tarjan. I don't think I've ever read a math text written in the third person e.g. "from here Pólya went on to talk about..." but it is surprisingly readable. I much preferred the first half, which recounts Pólya's lectures, than the second which covered Tarjan's. That is mostly just personal preference for the material covered.