This chapter introduces the concept of integrating Drupal with a third-party cache. It will examine the use, advantages and limitation of file-based caches. It will also review the use, advantages and limitations of using PHP opcode caches for caching other content. The chapter will detail the many projects helping with this integration, explaining their configuration and use. It will also review the many patches available for improving Drupal's caching, including the advcache project, block caching, and improved taxonomy caching. Finally, the chapter will provide an initial introduction to memcached.

1. File caches
   1. Boost module
   2. Fastpath_fscache
   3. Cache Coherency
2. Patching Drupal
   1. Advcache
   2. Caching Blocks
   3. Caching Taxonomy
3. Memory caches
   1. Opcode Caches
   2. Distributed Memory Cache