How do I transfer songs from an Ipod to my computer?

I found an 8GB nano in the grocery store last week, I let the manager know that I found it and he told me to wait about a week and if nobody claims it, then I can keep it if I wanted. Surprisingly, I never had an Ipod before bc I felt like I would never use it. But this one has a small FM transmitter attached so I can play it in the car. If it wasn’t for that, I’d probably just sell it.

******So this Ipod has over 1500 songs already on it…is there any way I can transfer these to be played on my computer? out of the 1500 songs, only 5 are purchased through Itunes******
Edit: I would like to transfer the songs on the iPod to my computer. However, in iTunes it won't allow me to click on the songs present on the iPod. Therefore, I can't drag the songs OR even play the songs from within iTunes.