They are the plums. Note that the duties of many such positions may involve advocacy of Administration policies and programs and the incumbents usually have a close and confidential working relationship with the agency head or other key officials. We get the point. These are appointments made by the president and his appointees. Beyond that, the book's 211 pages of tables describe an unfamiliar world.
Guidance is needed.
It is printed every four years in November. If you might seek empire through a plum, you will want to compare agency size with agency plums. Of course, you can measure empire by budget rather than by jobs. While the Plum Book lists about 9,000 jobs, news reports say total jobs available for political appointment by the new administration are about 3,000 or 4,000. While any SES job is eligible to be filled by political appointment, only 10 percent may be so filled at any time.