These are the Preface to the six published Hindi Film Geet Kosh volumes. Volumes 1, 2 , 3, 4 and 6 were compiled by Har Mandir Singh 'Hamraaz'. Volume 5 was compiled by Bishwanath Chatterjee under his guidance. The originals are in Hindi. Excellent English translations hare been prepared by N Ramaswamy, originally from Thrissur, now living in Kuwait.
They are a must read. They describe in detail the compiler's journey from being a curious teenager to world-famous compiler. You will be rewarded with all the experiences he had, with lots of good people helping him (and some others not so much). The prefaces can be read here
Note: Volume 5 was compiled by Bishwanath Chatterjee