This[0] is the book's page and this[1] is the direct link to the PDF (note: there is a reCAPTCHA).
The book is one of many textbooks that Springer has made available for download during the Covid-19 period (see here[2] for a complete list). While there have been prior posts about these free textbooks, I wanted to make a post about this specific book given how highly-regarded it is here on HN and because I expect that many of the people who might be interested in acquiring this title might well have skipped HN posts titled, e.g., "Free Textbooks from Springer, Categorized", thereby missing out.
P.S. If you like "The Algorithm Design Manual" and wish that there were a similar text about data science, Prof. Skiena's book, "The Data Science Design Manual" is also freely downloadable from Springer -- it is similar in style, e.g. conversational, with war stories, etc.
This[3] is that book's page and this[4] the direct download link (again, note: there is a reCAPTCHA).
[0] https://link.springer.com/book/10.1007/978-1-84800-070-4
[1] https://link.springer.com/content/pdf/10.1007%2F978-1-84800-070-4.pdf
[2] https://news.ycombinator.com/item?id=23520545
[3] https://link.springer.com/book/10.1007/978-3-319-55444-0
[4] https://link.springer.com/content/pdf/10.1007%2F978-3-319-55444-0.pdf