Intrinsic functions are built-in functions provided by AWS to use within a template for dynamically adding values. Common intrinsic functions used within CloudFormation templates are as follows: Fn::Base64, Fn::Cidr, Fn::FindInMap, Fn::GetAtt, Fn::GetAZs, Fn::ImportValue, Fn::Join, Fn::Select, Fn::Split, Fn::Sub, and Ref.

CloudFormation also supports the following conditional functions: Fn::And, Fn::Equals, Fn::If, Fn::Not, and Fn::Or.

We can specify the functions in the standard forms as mentioned here or in the short-hand form (for instance, !Base64, !Cidr, !Ref, and so on) if you are using YAML. We used the standard syntax for this recipe for reference, but will use the short-hand syntax in later recipes. 

We will discuss the functions introduced in each chapter. You can read more about all intrinsic functions at https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference.html.