I sold the last print copy of [Modern IDL] that I had this morning. At this time, I do not intend to make another print run; the PDF will be the only version of the book from now on[^1].
While I continually update *Modern IDL* for new versions of IDL, only the PDF purchasers get the full benefit of the updates. The hardcopy version was often a version of two behind because of the way that I placed orders to my printer. PDF purchasers also got future updates[^2], which was, of course, impossible for the hardcopy version.
For those who still really want a hardcopy version, you have permission to print your PDF. While higher, I think the total cost of the PDF plus printing/binding at Kinkos shouldn't be *too much* more than I was charging for the hardcopy.
[Modern IDL]: http://modernidl.idldev.com "Modern IDL"
[^1]: Although, I don't have anything against other electronic formats. If you have a favorite electronic format that you would like to see *Modern IDL* available in, please let me know.
[^2]: PDF purchasers will receive updates until IDL 9.0, when you will have to purchase again to receive further updates.