Summer squash are a subset of squashes that are harvested when immature (while the rind is still tender and edible). The name "summer squash" refers to the inability to store these squashes for long periods of time.
The delicate flavor, soft shell and creamy white flesh of summer squash is a perfect addition to any summer meal. Once only available in the summer, they are now available throughout the year; however, they are in season between May and July when they are at their best and most readily available.
Summer squash, members of the Cucurbitaceae family and relatives of both the melon and the cucumber, come in many different varieties. They are generally divided into four groups; crookneck, straight neck, scallop and zucchini. While each type varies in shape, color, size and flavor, they all share some common characteristics. The entire vegetable, including its flesh, seeds and skin, is edible. In addition, some varieties of the squash plant produce edible flowers.

History
Modern day squash developed from the wild squash that originated in an area between Guatemala and Mexico. While squash has been consumed for over 10,000 years, they were first cultivated specifically for their seeds since earlier squashes did not contain much flesh and what they did contain was very bitter and unpalatable. As time progressed, squash cultivation spread throughout the Americas, and varieties with a greater quantity of sweeter-tasting flesh were developed. Christopher Columbus brought squash back to Europe from the New World, and like other native American foods, their cultivation was introduced throughout the world by Portuguese and Spanish explorers. Today, the largest commercial producers of squash include China, Japan, Romania, Turkey, Italy, Egypt, and Argentina.
Nutritional Value: Summer squash contain few calories and no sodium or fat. They are a source of vitamins A and C. Nutritional Data
Selection and Storage: When purchasing summer squash, look for ones that are heavy for their size and have shiny, unblemished rinds. Additionally, the rinds should not be very hard since this indicates that the squash are overmature and will have hard seeds and stringy flesh. Purchase summer squash that are of average size since those that are overly large may be fibrous, while those that are overly small may be inferior in flavor.
Summer squash is very fragile and should be handled with care as small punctures will lead to decay. It should be stored unwashed in a plastic bag in the refrigerator, where it will keep for about seven days. While it can be frozen, this will make the flesh much softer. To do so, blanch slices of summer squash for two minutes before freezing. .
Preparation: Wash summer squash under cool running water and then cut off both ends. You can then proceed to cut it into the desired size and shape for the particular recipe.
Unlike winter squash, summer squash can be eaten rind, seeds, and all.  The different varieties vary in size, shape, and color, but they can be used interchangeably in recipes.  Select summer squash that's small and firm.