PDF is a very popular file format, created by Adobe in 1993. Its purpose is to create documents that will look exactly the same everywhere, even when printed. The only problem is that usually, the information contained in this type of files is not easily modified nor extracted by a machine. As expected the information it contains is arranged in a way it makes it easy to display the document, but makes it almost impossible to be read without a PDF reader.
To have an idea of how a PDF looks in its interior, open a PDF file with any text reader such as notepad in Windows. For those who’d like to have an introduction about the structure of PDF files, please read this carefully written article.
About a year ago I built a software utility to convert huge PDF tables to Excel files in order to work and manipulate their data.