If you are on a budget but need the 4th edition’s insights, you have better options than a shady PDF link:
Because this book is so popular, you can often find used physical copies of the 4th edition on sites like ThriftBooks or eBay for the price of a single lunch.
If you have access to LinkedIn Learning or O'Reilly Media through your school or work, the book is often included in their digital libraries. Final Verdict
R.A.P. principles specifically to see how it can improve your current projects?