National Learning Corporation is a widely available resource for custodian test questions and study guides. In addition, it offers exam resources for other fields including clerical, accounting, police and correctional officers, and teaching. These books are a part of the National Learning Corporation's series of test preparations called Passbooks.
These study guides are designed to emulate a real examination. The tests use the appropriate format and provide multiple streamlined questions and answers. Step-by-step instructions are included with all exam guides. Many counties, such as Monroe County, New York, provide sample test questions and study guides through the Department of Civil Service or the equivalent.