One of the film's most important ingredients is Robert Cobert's brooding, icy score which fits the movie like a glove.  His music is perfect from its slow and ominous beginning to the film's unexpectedly sudden and violent ending.  The closest that this score ever got to being released in any known version was when a handful of selected tracks were released on the compilation CD The Night Stalker and Other Classic Thrillers by Varese Sarabande in September 2000. 

Now, after thirty-five years, a new and long-overdue soundtrack album on compact disc, a limited edition of only 1,000 copies courtesy of Counterpoint, contains the film's complete score.  Additionally, there is the inclusion of several musical tracks that illustrate just how Mr. Cobert envisioned the film's opening. 

There are a total of 32 tracks on the CD:

1. Foreboding Evil 1:32
2. Memories Of A Lifetime 2:06
3. 17 Shore Road 2:08
4. Mrs. Allardyce's Room 0:53
5. Music Box Theme 2:50
6. Danger At The Pool 2:53
7. Funeral Dream 1:28
8. The Pool After Dark 0:32
9. Rendezvous Gone Wrong 2:10
10. Aunt Elizabeth Investigates 2:06
11. The Chauffeur 1:04
12. The Clocks Restart/The Gas Leaks 0:50
13. Marian & Aunt Elizabeth's Quarrel (Extended Version) 2:06
14. Aunt Elizabeth Falls Ill 4:42
15. Music Box Theme 1:29
16. Terror Up The Stairs 2:19
17. The Greenhouse 0:26
18. Rejuvenation and Attempted Escape 2:44
19. The Ride Back 1:32
20. Swimming Pool 4:52
21. Ben Confronts Terror 1:43
22. The Final Horror 1:29
23. A House Reborn/End Title 3:08
24. Marian Rolfe 0:32
25. House Eternal 1:42
26. Family In Danger 1:35
27. Main Title (Outtake) 3:18
28. Music Box Theme (Piano) 2:51
29. Alternate Music Box Theme #1 (Celesta) 1:06
30. Alternate Music Box Theme #2 (Piano) 2:21
31. Music Box Theme 2:37
32. Main Title (Reprise-Outtake) 0:45

Total Disc Time: 65:22

Among the creepiest tracks are the main titles wherein the credits slowly roll and the family approaches the house.  Originally, Mr. Cobert recorded upbeat music to counterpoint the family's fate, but director Curtis wisely jettisoned this in favor of the "Foreboding Evil" track which begins as soon as they set foot on to the house's property.  "Funeral Dream" is one of the scariest pieces of music written for any film, and it doesn't help that it's accompanying visual is that of Anthony James as the chauffer!  Goosebump-inducing chills abound in this one track alone.

The CD booklet is 20 pages long and is lavishly illustrated with never-before-seen photos taken on the set of the film during the August 1975 production. 

This is one of the best horror film scores ever written, and it's one of those scores that's worth owning even if you haven't seen the film. 

Order it here from Screen Archives Entertainment.  They are a phenomenal soundtrack album retailer with quick shipping!