The Bible for all cooks.
I may start with Potage Parmentier, but I doubt I will be making every recipe and blogging about it as in "Julie and Julia". Potage Parmentier is a favorite, and easy recipe (Potato and leek soup). Julia Child leads the cook through kitchen equipment, sauces, stocks, and basic pastry recipes to elegant complex dishes.
I also recommend reading "My Life in France" by Julia Child and Alex Prud'homme which traces the work that went into writing this cookbook and how it led to her TV show on public television.
I wonder if we would have Food Network now if it hadn't been for this book that changed how we cook and how we think about food. Remember the popularity of frozen TV dinners?