  We introduce the notion of a braided Lie algebra consisting of a
finite-dimensional vector space $\CL$ equipped with a bracket $[\ ,\
]:\CL\tens\CL\to \CL$ and a Yang-Baxter operator $\Psi:\CL\tens\CL\to
\CL\tens\CL$ obeying some axioms. We show that such an object has an enveloping
braided-bialgebra $U(\CL)$. We show that every generic $R$-matrix leads to such
a braided Lie algebra with $[\ ,\ ]$ given by structure constants $c^{IJ}{}_K$
determined from $R$. In this case $U(\CL)=B(R)$ the braided matrices introduced
previously. We also introduce the basic theory of these braided Lie algebras,
including the natural right-regular action of a braided-Lie algebra $\CL$ by
braided vector fields, the braided-Killing form and the quadratic Casimir
associated to $\CL$. These constructions recover the relevant notions for
usual, colour and super-Lie algebras as special cases. In addition, the
standard quantum deformations $U_q(g)$ are understood as the enveloping
algebras of such underlying braided Lie algebras with $[\ ,\ ]$ on $\CL\subset
U_q(g)$ given by the quantum adjoint action.
