We will be rolling out several small fixes mid-day today (Jan 29.) We do not anticipate any disruptions or problems, but f you spot any unexpected issues after 12 noon (PST), please report them in the designated thread in the DG Site Updates forum.
A good book on propagation. It is broken down into categories and tells you how to propagate things in those categories. Ex: perennials, bulbs etc. Each section also has a small directory of plants with plant information and pictures.