It appears there is no legal e-book or offline digital version of recent editions of the manual, at any price, with or without DRM. There is only the printed, hardcover edition, and a subscription-only, online-only website with the contents of the 17th and 18th editions, presented as a single paragraph per page, and poorly typeset, particularly for symbols. There's no legal way to obtain a long-term digital copy of a particular edition; it's not clear if the publishers intend to keep editions back to the 17th available online for the subscription, or only the two most recent editions: this is of relevance to me because I found the mathematics chapter particularly useful and unusual for style guides, and the authors decided to remove the entire chapter in the 18th edition.
Even if calculated as the cost of having access to an edition for the approximately seven years it remains the most recent, assuming the pricing doesn't increase, and using multi-year payments, the legal online-only access involves a subscription that would cost close to four times the list price of the hardcover book, something that you would own in perpetuity. It doesn't appear that the online subscription's content is continually updated, or that it offers any advantage over the book beyond being electronic, and having its page views used to motivate decisions like removing the mathematics chapter. It is a subscription, and online-only, merely by virtue of being a digital version of a printed book.
Meanwhile, readers who aren't concerned about using a pirated copy can easily obtain a clean, searchable, PDF from page images and OCR, with the book's typesetting, and more than one paragraph visible at once. This is, of course, usable offline.
The discrepancy between what is available to readers who want a legal digital copy, at any price, and readers who don't care, is quite disappointing.
Even if calculated as the cost of having access to an edition for the approximately seven years it remains the most recent, assuming the pricing doesn't increase, and using multi-year payments, the legal online-only access involves a subscription that would cost close to four times the list price of the hardcover book, something that you would own in perpetuity. It doesn't appear that the online subscription's content is continually updated, or that it offers any advantage over the book beyond being electronic, and having its page views used to motivate decisions like removing the mathematics chapter. It is a subscription, and online-only, merely by virtue of being a digital version of a printed book.
Meanwhile, readers who aren't concerned about using a pirated copy can easily obtain a clean, searchable, PDF from page images and OCR, with the book's typesetting, and more than one paragraph visible at once. This is, of course, usable offline.
The discrepancy between what is available to readers who want a legal digital copy, at any price, and readers who don't care, is quite disappointing.