Harper Collins has two Sally Wise cookbooks on Slow Cookers on sale today, although their email only mentions the first:
Slow Cooker: Easy and Delicious Recipes for All Seasons: $2.99
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The Complete Slow Cooker $3.99
The complete guide to slow cooking from Australia's number 1 slow cooking author. A bumper edition of recipes from the best known, best loved and the biggest selling author of books on slow cooking, Sally Wise. this combination of SLOW COOKER and SLOW COOKER 2 is packed full of Sally's great recipes, drawn from a collection created over thirty years of preparing tasty and economical meals for her family.
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I don't have either, yet, but it would appear The Complete Slow Cooker is the better deal if the latter contains all of the recipes from her Slow Cooker and Slow Cooker 2 books. The ad copy sounds like it probably does, and the claimed page counts make me suspect they do.