What is the highest level of a doctor?

There isn't a single "highest level" of doctor in the sense of a hierarchical ranking. The level of a doctor is determined by their specialty, years of experience, and achievements, not a single overarching title.

However, some positions and accomplishments could be considered to represent the pinnacle of a medical career, such as:

* Leadership positions: Heads of major medical departments, deans of medical schools, and surgeons general.

* Extensive research contributions: Doctors who have made groundbreaking discoveries and significantly advanced medical knowledge.

* Highly specialized subspecialties: Doctors in exceptionally niche areas requiring many years of additional training. For example, a neurosurgeon specializing in a specific type of brain tumor surgery.

* National or international recognition: Doctors who have received prestigious awards or have made significant contributions to public health on a global scale.

Ultimately, the "highest level" is subjective and depends on the criteria used. It's more about the impact and influence a doctor has on the field of medicine and patient care than a specific title or rank.