Her manuscript of 114 , "Book M" (BL, Add. MS 4454), was written over six or seven years during her period of mourning — her "Most saddest Yeares" (60r) — and includes material on her lawsuit, interpretations of dreams (her own and others), historical commentary, prayers, letters, financial materials, and 34 verse meditations in rhyming couplets. The richest source of information about Austen is her manuscript miscellany, "Book M," which includes over thirty occasional and religious lyrics on topics such as child loss, Austen's legacy to her children, a Valentine's Day gift, her prophetic interests, and of course, Highbury. It also contains spiritual meditations, including a short essay on Hildegard of Bingen, notes on sermons, comments on her economic affairs, and correspondence. She wrote the miscellany primarily between 1664 and 1666 and made changes to it until 1682. "Book M" demonstrates her familiarity with the poetry of Richard Corbett and some of John Donne's writings (certainly his sermons, possibly his poetry).