This is a time of critical increases in understanding membrane protein structures and their mechanisms in biology. As the first structures of membrane proteins determined by X ray crystallography from rich natural sources bovine rhodopsin bovine aquaporin from eye lens and proteins from mammalian tissues the advent of cloning and expression opened a broader horizon and first gave rise to predominantly prokaryotic membrane proteins expressed in a prokaryotic host. Eukaryotic proteins present greater challenges as their normal synthesis proceeds through cellular pathways inside the cell processed in the endoplasmic reticulum and Golgi apparatus. Thus as the number of membrane proteins is now increasing exponentially and primarily represented by prokaryotic species the numbers of eukaryotic membrane proteins is steadily increasing building toward the opportunities to understand targets of pharmacological significance. It emerges that different classes of receptors transporters pumps or channels often yield to crystallization using specialized techniques that serve to fix particular kinds of dynamical properties associated with transport or signaling. In this issue we sought to bring together a series of timely reviews that summarize several of the generally applicable technologies alongside others that have so far gained special advantage for certain membrane protein classes.