PDF files, how to?

[le capitan]

Im not sure if this is meant to be here, but its not exactly related to drawing, but...
how do you make pdf files. I can make individual ones but i cant add pages. Do I need the full program? why im asking is cause i want to make a pdf of the drawing heads and hands loomis book.
any help would be much apreciated. im only up to page 76 T_T theres 156 i believe so still a long way off.
thanks in advance

[Balooga]

Do you have Photoshop CS? Here's how I make multi-page PDF files with it: Open Photoshop CS, and choose File > Automate > PDF Presentation. Then, in the PDF Presentation dialog box, click the Browse button, and locate images on your hard drive that you want to be included in your PDF file. Next, under Output Options, make sure Multi-Page Document is selected, and then click Save. Name it and save it on your hard drive. Simple!

[SeraphSword]

Why not just download the pdf of Drawing Heads and Hands?

[Yiako]

In any application go to File > Print > Save as PDF.
At least in Mac Os.