Is it possible to read iBooks without an iOS device?

Solution 1:

OS X 10.9 Mavericks includes an iBooks app that allows you to read any documents - including purchased books or your own pdfs - that you had in iBooks for iOS.

Mavericks is a free upgrade available for the following systems, and was released on 22 October, 2013 through the Mac App Store.

From OS X Mavericks : System Requirements

To install Mavericks, you need one of these Macs:

iMac (Mid-2007 or later) MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later) MacBook Pro (13-inch, Mid-2009 or later), MacBook Pro (15-inch or 17-inch, Mid/Late 2007 or later) MacBook Air (Late 2008 or later) Mac Mini (Early 2009 or later) Mac Pro (Early 2008 or later) Xserve (Early 2009) Your Mac also needs:

OS X Mountain Lion, Lion, or Snow Leopard v10.6.8 already installed 2 GB or more of memory 8 GB or more of available space

Solution 2:

Apple has released an FAQ for iBooks where (as of January 2012), it says under
About iBooks and the iBookstore → What are the requirements to use iBooks?:

You can use iBooks on iPad. You can also use iBooks on iPhone or iPod touch with iOS 4 or later.

Until OS X Mavericks was released with iBooks for OS X, the answer was no.

Solution 3:

At this time Unfortunately, no.

There is no Mac OS X application for iBooks. You may want to submit a feature request to Apple.