My Book formatted for PC, but can I access data from a Mac?

I have a My Book that is formatted for my PC.  I have a Mac now and I’m wondering if I can plug in the external hard drive to my Mac and still be able to access the data on the external hard drive?  It’s mostly pictures on it and I don’t want to lose them.

A second part to my question is, if I can access the photos, can I some how move them to my Mac and put them on a different external hard drive?

Unless you reformatted the drive to FAT32 it will be read only on the Mac. I don’t know much about Macs see if this helps  seepost 6.