Here is the whole book scanned in color (114.6 MB, 407 pages): Pan Tadeusz
And here the same book in black-and-white (9.1 MB, 407 pages): Pan Tadeusz BW
This book was published in 1950 and based on my research it is in public domain. If you want to include books and other documents that you scan in published content, you should first verify if scanned content is in public domain - here is the link that can help you with this research.
If you scan books and other documents that you own for your personal use - here is another link about legal aspects and fair use scenarios.