The geoid is an equipotential surface of the Earth's gravity field that nearly coincides with the mean sea level. In regional geoid determination it has become customary to utilize a modified Stokes formula, which combines local terrestrial data with an appropriate global geopotential model. Two distinct modification classes - deterministic and stochastic, exist. Both approaches aim at reducing the truncation bias which occurs due to neglecting the far-zone integration. In addition the stochastic methods also attempt to reduce the data errors in geoid modeling. This book presents principles of high-resolution geoid modeling for the three Baltic countries - Estonia, Latvia and Lithuania. Six modification methods are studied and tested numerically. Even though emphasis is on one specific region, it is the intention of this book to present comprehensive guidelines of the applied methods that can be utilized in any given region worldwide. This book can be used as complementary text to graduate level courses in the discipline of physical geodesy. Researchers primarily interested in regional geoid modeling may also be interested in this book.