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Value of spell books
A standard spell book has an Experience Point Value of 1,000 points per spell level contained therein (considering cantrips as first level spells for this purpose), and a Gold Piece Sale Value of 200 gp per spell level (but only 150 gold pieces for each cantrip, if the book is of that sort). A travelling spell book has an Experience Point Value of 500 points per spell level contained therein (again, considering cantrips as first level spells), and a Gold Piece Sale Value of 1,000 gp per spell level (applies to all spells, including cantrips).
As with any other magical items, spell books must either be sold immediately or else the X.P. value taken. This holds true regardless of whether or not any tome is eventually sold. Thus, a spell book cannot be kept while a particular spell or spells are transcribed, and then the work be sold for G.P. Sale Value and
the proceeds taken toward experience points dragon mag, article by gary