  We study the elliptic algebras $Q_{n,k}(E,\tau)$ introduced by Feigin and
Odesskii as a generalization of Sklyanin algebras. They form a family of
quadratic algebras parametrized by coprime integers $n>k\geq 1$, an elliptic
curve $E$, and a point $\tau\in E$. We consider and compare several different
definitions of the algebras and provide proofs of various statements about them
made by Feigin and Odesskii. For example, we show that $Q_{n,k}(E,0)$, and
$Q_{n,n-1}(E,\tau)$ are polynomial rings on $n$ variables. We also show that
$Q_{n,k}(E,\tau+\zeta)$ is a twist of $Q_{n,k}(E,\tau)$ when $\zeta$ is an
$n$-torsion point. This paper is the first of several we are writing about the
algebras $Q_{n,k}(E,\tau)$.
