Fundamental to an understanding of the Roman Republic is comprehension of the tribal system employed to organize citizens. Used first for the census, raising an army, and tax collection, tribes later became voting districts for the election of magistrates. Voting districts were distributed geographi[...]

A fast-paced, non-technical and expert tour of how our solar system came into existence.

This innovative resource, created by Stephen Yeaple, was developed simultaneously with the textbook as an integral part of the teaching and learning system.[...]