With the ubiquity of the internet and popularity of the Internet Movie Database, it's easy to forget that there are many excellent film reference sources available only in print.
One of the best is the The Motion Picture Guide by Jay Robert Nash and Stanley Ralph Ross. Interestingly, for a period of time the text of this encyclopedia was online over a decade ago as part of the TV Guide's website. One also suspects that online resources like the IMDB and the Wikipedia have poached liberally from this source.
The Motion Picture Guide was originally published serially in nine volumes A-Z, plus a volume for silent films and two indexes. These volumes cover films from 1910 to 1983. The final volume of the original set also included a supplement for the films of 1984. Nash and Ross continued to publish annual volumes for every year up to 1998.
This encyclopedia gives the film's title, a lengthy (though not exhaustive) list of cast members, its year of release, running time, the production company, whether the film was black and white or color, its MPAA rating and its genre. For foreign films they point out whether subtitles or dubbing are used in the American version.
Most importantly the Guide rates each film on a scale from 0-5 and provides a thoughtful synopsis and review of each film. Some of these synopses are as short as a sentence, others as long as a page.
The production credits include information about the screenwriting and any literary source. They also provide the name of the music director, the name of any songs or notable music used in the film as well the songwriters and lyricists for this music.
As a good encyclopedic source should, the Motion Picture Guide also includes extensive indexes by country, distributor, genre, MPAA rating, and parental recommendation. Of course there is indexing by name, for actors, art directors, associate producers, casting, choreographers, cinematographers, co-producers, costumes, directors, editors, executive producers, makeup/FX makeup, music composers, producers, production designers, screenwriters, sound, source authors, special effects, and stunts,