I highly recommend buying the "large print" version, it's the size of most textbooks.

The smaller version is nice for reading while on the go/during a commute but not as nice for when you want to have it on your desk as a reference while working through problems (which you'll be doing a lot with this book). With the small version I have to find things to weigh down both sides just to keep it open on my desk so I can glance at it.