The document discusses security best practices for serverless applications. It emphasizes that application dependencies represent a large attack surface and inputs/outputs should be sanitized. The least privilege principle and compartmentalization are important, as is encrypting data at rest and in transit. Unused functions should be deleted, and threats like DoS attacks and credential theft should be guarded against. People can be the weakest link, so secure credentials and implement authentication. The document provides resources for further reading on these topics.