Currently, there is no clear path for working Haskell developers to learn how to write high performance Haskell code. Instead, performance improvement techniques are left to anecdotes spread across the internet, buried in technical documentation, or in comments in source code. This creates several second order effects in the community: it increases the barrier for Haskell’s adoption into industrial settings, it increases the difficulty in becoming an expert in Haskell, and it leads to slower code that is allowed to proliferate through the community and library ecosystem. These problems have been directly addressed in Haskell Foundation tech proposal 26, however the community has not been updated since the proposal’s acceptance. This talk seeks to update the community. In it I will introduce the Haskell Optimization Handbook (HOH). HoH is a freely available, online text book written for the working Haskell developer or interested Haskell hacker. It consolidates best practices for measurement, diagnosis, and optimization best practices into a single, unified document. Topics include the well-trodden, such as using GHC flags or tickyticky profliing; to magical, such as oneShot monads and backpack; to the third party, such as using valgrind and perf. Our hope at IOG is that the community will hear our call for contribution for the betterment of all.