What documents from the many available on the FDA web site are most helpful in understanding and preparing for FDA GCP inspections?

Compliance Programs. These documents all have standardized numbers, just like company SOPs. If you put the number into the search box on the FDA web page, www.fda.gov you will receive a list that will include the Compliance Programs you need. Key ones to retrieve are Compliance Programs 7348.810 (Sponsors, Monitors and CROs) and 7348.811 (Clinical Investigators). Pay special attention to Part III titled, Inspectional and Part V titled, Regulatory in these documents to learn what to expect during an FDA GCP inspection.