Can I make existing libraries use external SRAM for the Arduino I am running out of memory on my Arduino due to the libraries I am using. After I have included all the libraries I need then there is very little in the way of free memory for my own code.

If hook up some external RAM to the Arduino, is there a way I can make existing libraries use the external RAM rather than the SRAM on the arduino or will I need to alter the code in the library to do it.

If I have to modify the code is that a relatively easy thing to do?
Making a library use external SRAM is not an easy task. It can be cone, but it takes quite a bit of work.

The best start would be to abstract the SRAM into a library that provides simple access to it. Then you would need to use that new library to read and write data in the SRAM instead of accessing variables in the other libraries.

There is no way of simply mapping a variable into external SRAM - for that you need a microcontroller with an MMU  and/or an EIB.