Let $f:(X,\mathcal{R}_X)\to (Y,\mathcal{R}_Y)$ be the map between two topological space,with the sheaf of ring.
Given a sheaf of $\mathcal{R}_Y-$module $\mathcal{N}$,we can define the inverse image as usual by $f^{-1}(\mathcal{N})$ which is a $f^{-1}(\mathcal{R}_Y)-$module, define the pull back be the sheaf
$$f^*\mathcal{N} = \mathcal{R}_ X \otimes _{f^{-1}\mathcal{R}_ Y} f^{-1}\mathcal{N} $$ Here is an example: Given the inclusion $i:\{x\}\to X$ ,with $X$ the complex manifold with structure sheaf $\mathcal{O}_X$.prove the pull-back sheaf can be computed as :$$i^*\mathcal{N} = \mathcal{N}\otimes_{\mathcal{O}_{X,x}}\mathcal{O}_{\{x\}}$$
Moreover if taking $\mathcal{N}$ the sheaf of the sections over holomorphic bundle of $X$,then it's isomorphic to the firber of the bundle.