1. INTRODUCTION
2.2. Keck/MOSFIRE Observations
2.3. Emission Line Flux and Kinematic Measurements
2.4. HST Imaging
3. KINEMATICS AND SFHS OF GALAXIES AT $Z>3$
3.1. Kinematics of MOSEL Galaxies
3.2. Dynamical Mass Analysis
4. MASS ASSEMBLY IN COSMOLOGICAL SIMULATIONS
4.1. Disk-Size Comparison Between Observations and Simulations
4.2. Dynamical Mass Evolution
4.3. In Situ Versus Ex Situ Growth
5. DISCUSSION
5.1. Kinematics of Gas and SFHs
5.2. Mass Assembly History
6. SUMMARY