After two pilot movies, NBC greenlit "Columbo" as a regular rotating show in its "Mystery Theater" which aired weekly. "Murder By the Book" is the first "Columbo" airing in the series. It also has a distinction of being directed by a relatively new and inexperienced guy...Steven Spielberg.
Ken (Jack Cassidy) and Jim (Martin Milner) have together published some very successful murder mystery books starring Mrs. Melville--a Miss Marple-type character. However, Jim wants to end their partnership and write on his own, as he's both tired of Mrs. Melville and he's been doing almost all the writing. Ken decides to deal with this by murdering his old partner. But it's not a spur of the moment killing....Ken thinks he's very clever and thinks by planning it out and staging it properly he'll no doubt get away with the murder. However, as often is the case, he underestimates the police....and especially Lieutenant Columbo.
This installment works very, very well. Most of it is because Cassidy made an excellent villain...very smug, superior and self-assured. And, this might be why although this was NOT the first completed episode of the series, it was moved to the front...most likely to make a strong impression on fans.