  James Tree Space ($\mathcal{JT}$), introduced by R. James, is the first
Banach space constructed having non-separable conjugate and not containing
$\ell^1$. James actually proved that every infinite dimensional subspace of
$\mathcal{JT}$ contains a Hilbert space, which implies the $\ell^1$
non-embedding. In this expository article, we present a direct proof of the
$\ell^1$ non-embedding, using Rosenthal's $\ell^1$- Theorem and some measure
theoretic arguments, namely Riesz's Representation Theorem.
