Relational Algebra is a procedural query language consisting of a set of operations that take one or two relations as input and produce a new relation as output. The fundamental operations in Relational Algebra are selection, projection, union, set difference, cartesian product, and join. Selection chooses tuples that meet a selection condition, projection chooses attributes from a relation, union includes all tuples from two relations, set difference includes tuples from one relation not in another, cartesian product creates all combinations of tuples from two relations, and join compounds similar tuples from two relations.