I, too, recomment the Blue Book as a great guide to the basics, and another terrific book is
Small-Batch Preserving by Ellie Topp and Margaret Howard. It is filled with interesting recipes that take the basics one step further. For example, there are whole chapters on Chutneys, Conserves, Marmalades, Salsas, Flavored oils and vinegars, etc. All a little different, and great for gift giving, too.