Let me admit up front that I have only the vaguest sense of what S. Twomey's Introduction to the Mathematics of Inversion in Remote Sensing and Indirect Measurements is about. The main reason to note it here is to call attention to Dover's new series, the "Dover Phoenix Editions". These are hardcover reprints of classics in various scientific and mathematical fields "for which there has been a relatively small but steady demand."
Dover Publications has, of course, been reprinting valuable old mathematics books for many years. Their books range all the way from recreational mathematics aimed at the general public to highly technical books aimed at specialists. Inevitably, the latter don't sell as quickly, and sometimes that makes it difficult to keep them in print. The Phoenix series is an attempt to solve that problem.
The first batch of Phoenix editions includes 20 books, several of which deal with topics in pure or applied mathematics, including well-known classics by Osserman, Hurewicz, and others. Keeping good books in print is a great service to our profession; Dover's efforts are welcome and deserve our support.
Fernando Q. Gouvêa (firstname.lastname@example.org) is the editor of FOCUS and MAA Online.