It confused me, initially, that I couldn't find mention of a Burman-scored film entitled 'Aaj Raat Ko' on any movie web site anywhere. But then I discovered that while made (or at least shot) in 1975, it didn't actually come out until 1988, under the new name 'Faisla'. I'm not aware of the reasons behind the lengthy delay and title change, nor do I know if the soundtrack album was released prior to the production being aborted or if Polydor simply figured "well we have these new RD songs, might has well put them out there". The latter would at least explain the fact that the film's score only constitutes half an album.
To be honest, it's not a very memorable one. The only song I really like is Asha Bhosle's atmospheric, psyche-tinged 'Koi To Aye Ga Re'; that one is quite lovely. I'm unable to generate much enthusiasm over the rest. Perhaps additional and better songs were planned, I don't know. Side 2 is made up of four of 'R.D. Burman's Best'. Which, while by all means decent, they're not. I've posted most of them earlier.
Track listing, Aaj Raat Ko:
1. Asha Bhosle: Andheri Hai Raat Sajan
2. Mohd. Rafi: Champa Khilee Dar
3. Asha Bhosle: Koi To Aye Ga Re
4. Asha Bhosle & Kishore Kumar: Dulha Raja Mera
Track listing, R.D. Burman's Best:
5. Kishore Kumar: Ye Jawani Hai Diwani (from Jawani Diwani)
6. Kishore Kumar & Sushma Shreshta: A Mere Bete (from Aa Gale Lag Jaa)
7. Kishore Kumar & Asha Bhosle: Dil Machal Raha Hai (from Khalifa)
8. Kishore Mumar: Dheere Dheere Naach Re Jogan (from Bhola Bhala)