Dr. Roberto Galvan-Madrid was born in 1982 in Chetumal, Mexico, where he had his basic and high-school education. He obtained a bachelor degree in Physics from the Autonomous University of Nuevo Leon (UANL) in 2005, and a Masters degree in Astronomy from the National Autonomous University of Mexico (UNAM) in 2007. The thesis published here is a compilation of the work presented by RGM in August 2011 to obtain his Ph.D. degree in Astronomy from UNAM, under the supervision of Prof. Luis F. Rodriguez. During most of his thesis work, RGM was based at the Harvard-Smithsonian Center for Astrophysics (CfA), working as a Pre-doctoral fellow of the Submillimeter Array Project (SMA) under the supervision of Dr. Qizhou Zhang and Dr. Paul T. P. Ho. RGM's scientific interests are the processes of star formation, with emphasis on the formation of high-mass stars and clusters. Starting September 2011, RGM works as a postdoctoral fellow for the European Organization for Astronomical Research in the Southern Hemisphere (ESO).