This summary provides an overview of what is a GraphQL query, how it works, and how to write and execute them using Apollo Explorer. A GraphQL query fetches data, whereas a mutation changes data. The `query` keyword is optional but recommended for readability. GraphQL queries are plain strings that can be executed using various tools such as curl, fetch, or GraphQL client libraries. The Explorer IDE provides a workspace to run build, run, and save queries. It's beneficial to name queries for clarity. Queries can use nesting to ask for related data, and the `query` and `name` keywords are optional but recommended. A GraphQL operation can be either a query or a mutation, with queries fetching data and mutations changing data. The summary covers key points about GraphQL queries, including their usage, execution methods, and the benefits of using Apollo Explorer.