iBooks problems

I just purchased the new MacBook and have encountered a persistent and frustrating problem with iBooks: it only works intermittently! It freezes more than half the time I open the app (leaving me with no choice but to use the force quit option). In the best of times, it freezes temporarily (baiting me with the spinning color wheel while I wait for it to work again). I was actually experiencing a similar problem with my MacBook Pro 13" with Retina Display (mid-2014).

Is anyone else experiencing a similar problem? Might anyone suggest a resolution to this problem?