Recent observational and theoretical results indicate that smooth yet
efficient modes of gas accretion and internal secular processes may be
very important in the evolution of massive z ~ 1 - 3 galaxies. Studies
of the spatially-resolved dynamics, star formation, and physical
properties from near-IR integral field spectroscopy, now possible with
instruments such as SINFONI at the VLT, have provided some of the
first and most convincing evidence in support of this scenario. 
I will present results of such studies, including the SINS survey with
SINFONI of over 60 massive star-forming galaxies at z ~ 2. I will
highlight both detailed case studies and ensemble properties, and will
discuss the implications on the mass assembly, star formation, and
dynamical evolution of massive z ~ 2 galaxies.