I began my work at a time when invisibility was not fashionable at all.

Physicist Ulf Leonhardt, quoted here, in a piece noting how research into cloaking technologies has become popular and very nearly respectable. Needless to say, there are still one or two problems.

It’s difficult to find anybody in the know who expects there will ever be a device that hides itself and its contents at all wavelengths – if you can’t see it in visible light, then perhaps radar, infrared, ultraviolet or X-rays would reveal it. But optimism for practical uses is growing.

And there’s an issue I don’t recall being acknowledged in Star Trek. 

If a cloak were to make an object fully invisible to the outside world, then the outside world would be invisible to the object within the cloak. A thing (or person) inside a perfect cloak is not only invisible. It is blind.