  We present a number of investigations of 5d ${\cal N}=1$ supersymmetric gauge
theories that make use of 5-brane web constructions and the 5d superconformal
index. These include an observation of enhanced global symmetry in the 5d fixed
point theory corresponding to $SU(N)$ gauge theory with Chern-Simons level $\pm
N$, enhanced global symmetries in quiver theories, and dualities between quiver
theories and non-quiver theories. Instanton contributions play a crucial role
throughout.
