Whats the best (substantial) salad cookbook?

Just got mu June Bon appetite, and they have a really nice feature on amazing grain salads.

Kind of a quirky choice, but I've been enjoying going through "Twelve Months of Monastery Salads" by Brother Victor-Antoine d'Avila-Latourrette.

Thank you for so much helpful information.

food52 has many amazing recipes that fit your needs -- for example,
http://www.food52.com/recipe/salad%20vegetarian%20grain
Use the search box (top right) -- try specifying a specific grain or bean. You can always add or sub what you have on hand.
I also love using the cook books I already own with Eat Your Books (online subscription service) as a master index for my own books.
The whole concept lends itself to experimentation. I recently made a delicious avocado-based salad dressing, http://www.food52.com/recipes/17417_grilled_steak_and_mango_salad_with_avocado_buttermilk_ranch_dressing, and I'm using it in all sorts of combinations.
Quinoa is a good base, light, quick and easy to cook, and a complete protein (plus iron, calcium). http://www.food52.com/recipes/10549_red_quinoa_red_lentils_a_salad is one of mine -- adding vegetables would make it more of a full meal.

The most recent issue of Fine Cooking has a great spread on how to create grain salads--all sorts of flavor profiles, etc. I have found it very handy.

I second 101 Cookbooks - or if you want the blog authoer's hardcopy book, "Super Natural Every Day" by Heidi Swanson.

Another option is Mark Bittman's "How to Cook Everything" or "How to Cook Everything Vegetarian". Both have thematic sections on grains/salads and lots of substitution suggestions, so you can adjust recipes to what you have on hand. The books lack pretty pictures but make up for it in solid general cooking techniques and theory. Fits well with your unexpected guests criteria.

Another place to browse what you are looking for is Barnes and Nobles. I agree with amysarah, love Patricia Wells books.

Patricia Wells' Salad as a Meal is a good one - not specifically vegetarian, but it includes many meatless recipes: http://www.amazon.com/gp/product/006123883X/ref=as_li_tf_tl?ie=UTF8&tag=doriegreenspa-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=006123883X

Check out http://www.101cookbooks.com/, if you like her recipes, you may want to order her book. I really like her recipes.

Actually Plenty is my favorite cookbook. and I already made many recipes from this book and loved every single one of them. But, even though they're incredible, they're too sophisticated and time consuming for what I'm looking for.

I also own Vegetarian Cooking for Everyone and it looks promising but I'm still getting to know it.

Anyway, my quest is for a book full of simple and fast deli-like which almost don't require cooking. Where you can just mix beans, mushrooms, grains, peas, corn and raw greens.

Vegetarian Cooking for Everyone by Deborah Madison - has won some big awards. http://amzn.to/Ln9wsp. Good variety of dishes including pasta, grains, etc. that can be scaled up for a crowd.

I love Ottolenghi's Plenty - it's my favourite cookbook overall. Most of the recipes easily scale up and are beautiful, flavourful and written very well to ensure success.