• We have made the decision to offer our books as PDFs without DRM (digital rights management). We looked at DRM options and decided that the potential reduction in piracy was not worth the inconvenience to the customer in terms of higher prices and more-limited reading options. We were also concerned about reported glitches for some readers. We believe the PDFs we produce should be compatible with virtually all PDF readers, though some minor differences in appearance may be encountered among them. Should you have any issues viewing a PDF file, we would ask you to please contact us.

• We have opted to use a service that stamps each page of our textbook offerings with the purchaser's name, email address, and a unique transaction number as a relatively unobtrusive means of discouraging piracy. We are respectfully requesting that any purchases be made on this website (which, at this point, is the only legitimate source for our books) and that the purchaser will please refrain from sharing copies of our books. We are simply asking that the customer will respect the many hours we have put into creating our eBooks at what we believe are fair prices.

• Please note that our eBooks are yours to keep, as opposed to many electronic textbooks, which are often rented for a limited period of time and in some cases must be viewed online. Our non-textbook offerings are of course also yours to keep.

• We have attempted to make a reasonable compromise between image resolution versus file size. Pages will generally fit the screen at 100% view on ultra high-resolution computer displays and TVs* (*with appropriate hardware/software). A very few images in our textbooks were only available to us as low-resolution files and may exhibit a somewhat greater degree of pixelation. (Note that as you zoom in on a page, text and line-art illustrations scale up and look crisp but photos will pixelate at some point.) With so many different computer platforms, operating systems, and mobile devices available, we have not been able to test the PDFs on every combination and so we ask that you contact us if you should have any issues.