If anyone finds that TempleOSBooks1.iso and TempleOSBooks2.iso are missing and unavailable for download, i found them on a Reddit thread, and uploaded them to Amazon S3:
https://atlas-adventuring-ai.s3.amazonaws.com/TempleOSBooks1.ISO.C
https://atlas-adventuring-ai.s3.amazonaws.com/TempleOSBooks2.ISO.C
Take care.