No completely logical arrangement of these books is possible, due to multiple use of the same book, to the existence of the same accounts in draft and final form, and to the fact that in his old age Lord Milton repeatedly revised and extracted old accounts. The basic division into ledgers and other books (subdivided by size) goes back to him. Most are in his own hand, a few (in whole or in part) in those of his clerks. Personal, estate, and professional matters are all included.