: This is the most reliable source for a full digital copy. You can often "borrow" the book for free in one-hour or 14-day increments. Multiple editions, including the 1993 2nd edition, are available. View Essentials of Molecular Biology at Internet Archive
What is your current (high school, undergraduate, or advanced)? : This is the most reliable source for a full digital copy
Need to double-check if there are any open access versions. Maybe some chapters are available on Google Books or the publisher's website. Also, consider mentioning ebrary or Gale Virtual Reference Library if their institution subscribes. But since I can't know the user's institutional access, keep it general. View Essentials of Molecular Biology at Internet Archive
Many free PDF links are fronts for phishing scripts, spyware, or ransomware. Also, consider mentioning ebrary or Gale Virtual Reference
Many older editions of David Freifelder’s works are available to borrow digitally for free.
If you need a permanent copy for your personal library, these platforms offer the book: Essentials of molecular biology : Freifelder, David, 1935 29 July 2022 —