The Special Theory of Relativity:

Based on a short course of lectures delivered in the late 1930s, this short book presents the theory of Special Relativity by formulating a redefinition of the measurement of length, and thus will appeal to students of physics who wish to think through Einstein's thought without the encumbrance of quasi-scientific concepts and language.

Relativity: A Very Elementary Exposition:

This brief lecture, delivered in October 1921 and published for the first time in 1925, offers an explanation of Einstein's theory of Special Relativity for the non-scientist, giving a general overview that does justice both to the actual physics involved, and the wider implications of this revolutionary discovery of the 20th century.