A hypersurface in a compact manifold $M$ with boundary is called a free boundary minimal hypersurface (FBMH) if it is minimal and meets the boundary of $M$ orthogonally. Such hypersurfaces arise naturally as critical points of the area functional in $M$. If we do not assume any boundary convexity of $M$, then the FBMH may be improper, i.e., the interior of the FBMH may touch $\partial M$. We will discuss the compactness and existence results for FBMHs in this general setting.