The structure of the question begs the response 'no they're invisible....' but thats not very helpful or useful....

Free Hex Editor Binary File Editing Software for Windows

That link is to a free hex editor that says it can edit .dll files.

Decades ago I used to use a hex editor to alter the saved character files of some games i played. looking at a file in Hex is not very informative, but with an editor and a saved game file you can just mess with stats and come out with random stuff in your inventory.

If your wanting to alter it to do something useful, maybe a hex editor is not the best choice. See how it goes.

On a technical you can view .dll files using a normal notepad or text editor, but you would not make sense of it LOL.

You could always do what ussher suggested and use a Hex Editor. However, it sounds like you are wanting to make changes inside the .dll (trying to crack something), in that case you would need two things :-

1] Find out what language it was originally coded in,
2] Get a decompiler for that language and pass your .dll through it.

Please note that I no way advocate this type of approach. I am only suggesting this on a learning basis.

You can edit a lot of dll files using a software "Resource Hacker". Its a free software use it maybe it will help..

It's possible to see if you use a decompiler and the dll is not crypted. Can you change something in the dll? Possible, after some heavy reverse engineering.

A DLL is a library file that contains functions for other programs to use. In order for these functions to be run their code must have been compiled. Compiling is the process of taking source code in a language like C++ or Visual Basic which can be read by humans, and converting it into machine code that can be read by a computer processor. As such it is very hard to 'read' DLL files as the actual functional code is machine code. In order to read the source code you would have to attempt to reverse-engineer the machine code. Reverse compilation is touchy legal area which is usually very hard as the machine code may have been written in any high-level language, you would have to find out which one it was written in to have good shot of decompiling it. It would also likely be encoded.

I personally use OllyDbg it is a great tools for editing DLL, exe and other files.

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