Everyone uses Drupal's field system, but few engage the power of creating custom field types. Some have complained about the perceived inefficiency of Drupal 7's database schema, and proposed alternatives like 'pbs' module have failed to take hold, perhaps because there is a better way. Developers who want to implement complex, multi-value fields, or who wish to maximize control of database schemas for fields need to understand the Field APIs to be presented in this workshop.