The Merck index: an encyclopedia of chemicals, drugs, and biologicals, Susan Budavari, ed.

Now in its twelfth edition, the Merck index continues to be a big happy book of chemicals and what they're like. Entries tend to include typical chemical stuff -- molecular weight, boiling point, chemical formula, etc -- but also includes the LD50, notes on poisonous aspects, commentary on medical or vetinary uses, and all sorts of good stuff. Published by Merck research laboratories, the R&D wing of Merck.