Mr. Murphy over at The Silver Key has a review of Moldvay's rulebook:
I still own the same careworn copy of Moldvay basic that I bought back in 1981-82 or so. As I look at it now it remains a marvel of utility, organization, inspiration, and playability.
To begin with, Moldvay basic comprises a total of 64 pages. Take away the title page, foreward, and glossary, and you have a total of 60 pages. Heck, there are longer modules than this. By way of comparison, a single issue of Dungeon and Dragon magazine exceeded 100 pages towards the end of their run!
When combined with Cook's Expert D&D rulebook, you get a complete game for 128 pages. It's amazing how much goodness is compressed into so few pages, especially when you consider how frequently art and tables are included.