I can't read my eBooks I purchase from iTunes on my desktop or laptop. Do I need to go Amazon? Kindle?

Is there a future upgrade or availability to read eBooks purchased from iTunes on my desktop or laptop Mac?

If not, I am just going to get the free Kindle application and buy all of my ebooks from Amazon as I can read them on any Mac.

I purchased a book from Apple yesterday so that I could read it as a break during my work day at my office and it would not open. I checked and sure enough, you can't read books on your desktop Mac using Apple software. I tried the Adobe Digital software and a couple of others but the protection on the ebook prevented anything but my iPad or, if I had one, iPhone from reading it.

Considering that I spent many thousands on getting the best Macs for work and only hundreds on the pad, it is just a little irritating that I can't read a book on the pro machinery but can on the consumer toy.