I originally saw The Andromeda Strain (1971 Universal Pictures; directed by Robert Wise) in the theater. I was a high school biology student, and I was impressed at the time by how much science was actually in this picture. It reminded me of my classes and even of some of my teachers.
Based on the book of the same title by Michael Crichton (at the time a medical student who is shown in the background during one scene), the film contains a good amount of scientific background information, and it is a good science procedural as well as techno thriller. The pacing is slower, allowing more time to think while watching. Robert Wise was an excellent and well known director, and this is far from being a B movie.

The plot unfolds at an intriguing pace, and thisĀ movie contains elements of horror, suspense, and mystery.
The special effects were excellent for the pre-CGI era, and the look has aged well. Production values were good, taking advantage of real scientific equipment for many scenes. The underground research facility was well-designed.
What really intrigued me was the discovery and description of the extraterrestrial pathogen. This is perhaps the most original concept for an alien life form that I have seen in a movie. Keep in mind that this idea was groundbreaking at the time of the book’s publication and the subsequent release of the movie.
If you haven’t seen this, I heartily recommend this refreshing view from an earlier time in the development of science fiction.