Mom Textbooks?

I have a hard time buying books. I love getting rid of things I don't use so unless it's one of my favorites or I know I will use often, I won't buy it. Plus, why drop $10-20 on a book when there's a free library system to use? We do have two full bookshelves in our house but I've only read a few of the books on them more than once. Here are a few:

The Scarlet Pimpernel: This is probably my favorite novel. Thanks to the Campbell Ward book club for introducing me to this one.

I bought this before Trevor was born and still use it sometimes. It lists baby topics alphabetically and I like that "encyclopedia" style.

Lately I have been wanting to buy more parenting books so I can easily read about something when I need it rather than wait for the library reserve system. I thought about the money they would cost and the space they would take up at home. But then I remembered Birch's textbooks (and mine, even though most are in storage). Feeling justified, I bought another "mom textbook," Love and Logic. I've read it before but want to read parts again.

I think my friend Kat recommended this book and I like what I've read so far. I had to return it to the library before finishing because of that darn reserve system so this might be my next purchase.

What parenting books do you own or wish you did?