PostgreSQL Performance Tuning is a four-part series aimed at helping users fine-tune their database for performance as data and query volume grow. The first part focuses on sizing the database, particularly CPU and memory, to address predictable performance issues such as slow queries and high CPU usage. Key components include understanding CPU scaling, estimating maximum queries per second based on available cores, monitoring actual system performance, and adjusting resources like shared buffers and work mem to optimize data access and intermediate data structure creation. Understanding indexes and schemas is also crucial in fine-tuning the database for optimal performance. The series emphasizes that there are no foolproof guidelines and that experimentation and observation are necessary to achieve optimal results.