"Aren’t they in your book?" (56:8). What is God's book?

Psalm 56 asks the question about what it has just named, the psalmist's wanderings and tears, and doesn't explain the book. Its word, sifrah, comes nowhere else in the Hebrew Bible (tap book). Other verses speak of a book of God with the common word sefer, and they don't all speak of the same thing. Moses said, "please blot me out of your book which you have written" (Exodus 32:32), and the LORD answered, "Whoever has sinned against me, I will blot him out of my book" (Exodus 32:33). A psalm speaks of "the book of life" (Psalm 69:28), another of days: "In your book they were all written, the days that were ordained for me" (Psalm 139:16), and Malachi of "a book of memory" written "for those who feared the LORD" (Malachi 3:16). Psalm 56 doesn't say which of these, if any, it means, and these notes don't choose. What it does say, just before, is "You count my wanderings" (56:8).