For the main part of this dissertation, I have performed a survey of nearby, main sequence A, F, and G-type stars with the CHARA Array in order to determine their angular diameters to better than 4\% accuracy. In determining these quantities, I have established effective temperatures for these stars (to better than 2\% accuracy) as well as absolute luminosities, critical to testing stellar atmosphere and evolution models, as well as the practical application of accurately plotting the temperature-luminosity version of the H-R diagram. The accuracy and target sample range are aimed at refining, as well as expanding, the existing diameter measurements, which are used in the calibration of numerous less direct methods to predict stellar diameters and other fundamental properties of these types of stars. To-date, I have successfully measured the diameters of forty-four new stars.

The directly measured quantities of these forty-four CHARA stars are compared to results from 1) models results in three other published surveys, and 2) a large sample of eclipsing binary stars. I find that for most cases, the models underestimate the radius of the star, while in turn they overestimate the effective temperature, with no apparent correlation to a star's metallicity or color index. Masses are derived from the combination of $\log g$ estimates and measured radii of the CHARA stars, and they are compared to the masses in each of the above references, as well as for masses of eclipsing binaries. Yonsei-Yale ($Y^2$) model isochrones are fit to the CHARA determined temperature and luminosities to determine ages and masses of the entire target sample. Excellent agreement is seen in the relationships with binary stars, while masses from the $\log g$/radius method are typically underestimated as a consequence of $\log g$ offsets. A multi-parameter solution is found to fit color-temperature-metallicity values of the stars in this sample to provide a new calibration of the effective temperature scale for these types of stars. .