This study introduces the stages of the development of quantitative history through its main scholars and schools, then presents some statistical innovations and methods to estimate the inhabitants and populations of some Islamic cities throughout history, using a number of Arab and Western studies. This research has relied on quantitative approaches, demographic theories, and sought to utilize old texts and the statistical inferences found throughout these texts. The study also employs mathematical inferences that can be drawn from the spacial dimensions of these cities and the number of their public facilities, in as much as these inferences provide indicators of the dynamics of population size and growth in these cities. These quantitative approaches are certainly an important addition to the study of the history of Islamic societies. However, their systemic gaps reveal their limits and their relative nature. The utilization of these kinds of quantitative approaches can be risky if they are not historically and cognitively situated. This caution is in no way an attempt to dismiss these quantitative approaches, but rather a call to strengthen them using a more cautious and controlled approach.