The isspace() method in Python is a valuable string method used to determine if all the characters in a given string are whitespace characters. In Python, whitespace characters include spaces (' '), tabs ('\t'), newlines ('\n'), carriage returns ('\r'), and other Unicode-defined whitespace characters. This method returns True if all characters in the string are whitespace and False otherwise. The python isspace method is often used in text validation, parsing, and formatting tasks, making it an essential tool for Python developers working with string manipulation.