AngularJS is a JavaScript-based open-source front-end web application framework that was initially developed and maintained by Google. It's important to note that AngularJS (often referred to as Angular 1.x) is different from Angular (2 and above), which is a complete rewrite of the framework. As of my last knowledge update in September 2021, AngularJS is considered a legacy framework, and its use is not recommended for new projects. However, I'll provide you with some key information about AngularJS development:

1. Getting Started:
   - To start working with AngularJS, you need to include the AngularJS library in your project. You can download it from the official website or use a content delivery network (CDN) to include it in your HTML file.

2. MVC Architecture:
   - AngularJS follows the Model-View-Controller (MVC) architecture. Your application's logic and data are separated into models, views, and controllers.
   - Models represent your application's data.
   - Views display the data to the user.
   - Controllers handle user input and perform actions.

3. Data Binding:
   - One of the key features of AngularJS is two-way data binding. This means that changes to the model are automatically reflected in the view, and vice versa.

4. Directives:
   - Directives are special markers in the DOM (Document Object Model) that tell AngularJS to attach a specific behavior to an HTML element. Common directives include ng-model, ng-repeat, ng-show, and ng-hide.

5. Dependency Injection:
   - AngularJS provides a built-in dependency injection mechanism. It helps manage the dependencies of your application, making it easier to test and maintain.

6. Routing:
   - AngularJS has a routing module that allows you to build single-page applications (SPAs) with multiple views. It lets you define routes and associate them with templates and controllers.

7. Services:
   - Services are singleton objects in AngularJS that can be used to organize and share code across different parts of your application, such as controllers and directives.

8. Testing:
   - AngularJS has a strong focus on testability. It includes built-in support for unit testing and end-to-end testing, making it easier to write and maintain tests for your application.

9. Community and Resources:
   - While AngularJS is considered a legacy framework, there is still a community of developers who use and support it. You can find documentation, tutorials, and libraries to help with your development efforts.

10. Migration to Angular:
    - If you're working with an existing AngularJS project, it's worth considering migrating to Angular (2 and above) for long-term support and modern development practices. Migration tools and guides are available to assist in this process.