A personal library is perhaps one of the most important resources and source of inspiration for an artist. Being able to grab a book off the shelf and find a particular artist, artistic style or artwork is invaluable when researching for your own work. Also studying the work of other artists - whether they work in your same medium or not - always provides an immediate spark of inspiration that sends me reaching for clay.
In building your personal library, it will probalby start with some of the art history books you have from grad school, but there are many great places to build from there. New books are great, but also expensive. I've found some of my best books (some of them treasures!) at used book stores. Exhibit catalogues are a must - at times the museum store will have catalogues from past exhibits on sale. You can also look up past exhibit catalogues at one of my favorite used book sites www.addall.com and click on their 'used books' tab. However, a word of warning - from experience - if you love an exhibit go ahead, search all your couch cushions for loose change and buy the exhibit catalogue. I searched for months before I found one catalogue from a past exhibit that hadn't doubled in price since the exhibit closed.
Another great source is www.doverpublications.com they have reprints of books from the masters and some great collections of artist's works, they are also inexpensive. Watch out for the 'order $50 and get free shipping' bait - it's like shooting fish in a barrel with us! Seriously though it's a great site and has some great books.
For those of you that are potters or sculptors, you will have discovered that finding art books on painting and painters is everywhere, and it's harder to find books (especially used books) on the three dimensional arts - but keep an eye out, it's always a joy to find some old out of print tome that discusses your favorite artist or medium.
One last bit of advice - don't loan your books out. I've lost some good books to some great folks that way! the best approach I've found is one that I've borrowed from one of my art professors..... when someone walks into his library and sees his expansive collection of books on art - they invariably find one and ask "Can I borrow this one?" he would answer, "no, but you can come here and sit in this chair and read it anytime you want to."
So, keep reading, keep looking and keep building - an artist's personal library is one of their strongest assests.
"When I have money, I buy books, if there is anything left, I buy food and clothes"