By Provides a mechanism by which to find elements within a document.

 Cookie Represents a cookie in the browser.

 ElementNotVisibleException The exception that is thrown when an element is not visible.

 IllegalLocatorException The exception that is thrown when an attempt is made to locate an item using invalid criteria.

 InvalidCookieDomainException The exception that is thrown when the users attempts to set a cookie with an invalid domain.

 InvalidElementStateException The exception that is thrown when a reference to an element is no longer valid.

 InvalidSelectorException The exception that is thrown when an element is not visible.

 NoAlertPresentException The exception that is thrown when an alert is not found.

 NoSuchElementException The exception that is thrown when an element is not found.

 NoSuchFrameException The exception that is thrown when a frame is not found.

 NoSuchWindowException The exception that is thrown when a window is not found.

 NotFoundException The exception that is thrown when an item is not found.

 Platform Represents the platform on which tests are to be run.

 Proxy Describes proxy settings to be used with a driver instance.

 Screenshot Represents an image of the page currently loaded in the browser.

 StaleElementReferenceException The exception that is thrown when a reference to an element is no longer valid.

 UnableToSetCookieException The exception that is thrown when the user is unable to set a cookie.

 UnhandledAlertException The exception that is thrown when an unhandled alert is present.

 WebDriverException Represents exceptions that are thrown when an error occurs during actions.

 XPathLookupException The exception that is thrown when an error occurs during an XPath lookup.

 PlatformType Represents the known and supported Platforms that WebDriver runs on.

 ProxyKind Describes the kind of proxy.

 WebDriverResult Specifies return values for actions in the driver.

 Keys Representations of pressable keys that are not text keys for sending to the browser.

 IAlert Defines the interface through which the user can manipulate JavaScript alerts.

 ICapabilities Capabilities of the browser that you are going to use

 ICookieJar Defines an interface allowing the user to manipulate cookies on the current page.

 IHasCapabilities Defines the interface through which the user can determine the capabilities of a driver.

 IHasInputDevices Provides access to input devices for advanced user interactions.

 IJavaScriptExecutor Defines the interface through which the user can execute JavaScript.

 IKeyboard Provides methods representing basic keyboard actions.

 ILocatable Defines the interface through which the user can discover where an element is on the screen.

 IMouse Provides methods representing basic mouse actions.

 INavigation Defines an interface allowing the user to access the browser's history and to navigate to a given URL.

 IOptions Defines an interface allowing the user to set options on the browser.

 ISearchContext Defines the interface used to search for elements.

 ITakesScreenshot Defines the interface used to take screen shot images of the screen.

 ITargetLocator Defines the interface through which the user can locate a given frame or window.

 ITimeouts Defines the interface through which the user can define timeouts.

 IWebDriver Defines the interface through which the user controls the browser.

 IWebElement Defines the interface through which the user controls elements on the page.