Simple and concise, this survey of the fundamental principles of the method of least squares includes everything essential to the solution of ordinary problems. Frequent references throughout the text assist students in further extending their studies. Starting with an overview of general principles, the text proceeds to examine the adjustment of observations and the precision of observations. Additional topics include the computation of the precision measures and a consideration of miscellaneous theorems. The treatment concludes with a survey of Gauss's method of substitution.