I. Introduction  
II. Principles of mmWave Radars  
III. General Problem Formulation  
IV. Odometry Evaluation Metrics  
V. Radar Datasets  
VI. Radar Odometry  
VII. Radar Odometry and Sensor Fusion  
VIII. Radar Odometry and Machine Learning  
IX. Discussion, Challenges, and Future Recommendations  
X. Conclusion  