• Introduction
• Supersymmetry
• Two-Dimensional Conformal Field Theory
• String Quantization
• The Free String
• String Interactions
• String Field Theory Compactifications
• Orbifolds and Orientifolds
• T-Duality
• T-Duality
• M-theory

The metric has signature ${\displaystyle (+,-,-,-,...)}$.

Greek letters from the middle of the alphabet ${\displaystyle (\mu ,\nu ,...)}$ denote coordinates in spacetime. Roman letters taken from the beginning of the alphabet ${\displaystyle (a,b,...)}$ denote coordinates on the worldsheet.

The metric is denoted ${\displaystyle g_{\mu \nu }}$. In the case where there is a metric of spacetime and a metric of the worldsheet, the worldsheet metric is denoted ${\displaystyle h_{ab}}$

A lower-case ${\displaystyle d}$ is the number of dimensions. An upper-class ${\displaystyle D}$ represents the number of spacial dimensions.