Often coming as a Surprise, by default in some earlier presentations (like B/X) transcribing Spells from captured Enemy Spellbooks isn’t part of the Rules. This omission might seem a little strange (because it would quickly become more codified and taken for granted later) and sometimes stand out as a bit of a Proud Nail in terms of Spell Acquisition. Although a lot of Referees endeavor to graft this onto their games anyway, I always try to make sure that these types of Treasures have other interesting content, above and beyond a lovely list of new Spells a Magic User can add to their Repertoire to make them still worth lugging back to safety for later, more thorough examinations.
Here’s a table that expands upon this a bit. By placing a little lagniappe in these ledgers, they sometimes become useful Treasures in their own right, or at the very least become more memorable to the Players. Building a Library is a fruitful Downtime Activity that some Magic Users choose to pursue after all, and often this can add some intrinsic Value to an otherwise non-descript Spellbook. Sometimes these might still require that requisite Read Magic to decipher their function of course, but I love the idea of Spellbooks that contain more than just Spells: Functioning as a Workbook/Journal/Commonplace Book for the owner as well, conveying a little personality or odd habits/interests that they might have possessed.
