What's the best way to organise a history bookshelf?

By Size? Period? Read vs Unread? Topic? An arrangement of books that just looks good? What's the best way to organise a history bookshelf? Is there a tried and tested way out there that combines perfectly practicality with aesthetics?

You all know what I'm talking about, there is no historian out there who has not, at some point, lamented the demise of high-street book shops because, unlike online shops, it gives us the opportunity to go in and caress and ogle aesthetically pleasing history books with great looking covers and attractive spines that would just look so good on that shelf that guests see in your house or office.

Is aesthetics everything however? Do some of us get an internal aesthetic joy from our history bookshelves knowing that they are organised to a concise and accessible system that suits our own temperaments perfectly?

To find out I put the question to the history blogosphere and it sparked some interesting thoughts and opinions with a wide range of attitudes toward them.

Here are some of the replies I received on the subject via Twitter; let me know your own thoughts in the comments below.

Organized by region, chronologically within regions. Including Americas as one region, for ideological reasons. (@dpmckenzie)

Period and topic so I can find things quickly. My problem is remembering whether they are at home or in the office. (@historybeagle)

I organize by geographic region and within regions thematically. (@CarlySimpson)

Alphabetical by author's last name to find books easily. Or is that just me? (@markcheathem)

I arrange by topic and size! (@Historybuff19)