【解答】many a 和 a many，这两种说法都是比较古老的，含义却是一样。

        many a book = many books. 可见不要冠词单说 many 时，也就是现代英语了。

        至于a many，如果加上 great 或 good 的字样到 a 与 many 之间，而成为 a good many 或 a great many 时，又成为现在颇为通行的说法了。a great many (很多) 比a good many (相当多）语气要来得重些。例如:

         In my mouth, there are a good many teeth. (我口里有相当多的牙齿。) 

         There we saw a great many interesting things.(在那里我们看到许多有趣的东西。)          

         Many a = many times a (屡次有一个)；each one of many (几多，多数中的每个)，现代文中仍有时见到，如 Many a man has tried to get rich without success. (许 多人力求发财都来成功。) Many a mickle makes a muckle.(集腋成裘)。Many a true word is spoken in jest.(谐谑中易出真言。）   

         A many 的说法就更古了。在表多数的 many 一字前，加上不定冠词的a，岂不变成 “一个许多”了，初初看去，好很矛盾似的，其实语文这东西，是只重习惯，而不重理智的，许多不合逻辑的说法，只要看惯了，也就不觉得有什么不通了。例如 few 也是表多数的，为什么说a many 你觉得奇怪，说a few 就不觉得奇怪了呢；这不过是习惯使然罢了。

        A few的用法是从十三世纪开始的，大约是由此类推的结果，到了十六世纪时，便有a many 一个说法的出现。Shaken speare 就有不少a many的用例，如： 

        I do know a many fools.(A Merchant of Venice, IIl, v. 73) (我知道有许多傻子。) 

        A many merry men.(As You Like it, I, i, 121) (许多快乐的人们。) A many men refused to recognize his authority.(许多人都不承认他是 是权威。） 

        英国诗人Tennyson 在AMidber's Danghter一诗中，也有： 

        They have not shed a many tears, Dear eyes.(那双眼睛并没有流出多少相来。) 

        在《牛律大群典说“a many”is now somewhat rare in litcrary use.(在文学上也少用了），不过我们知道在促俗语(vulgar speech)中，却仍然在用，如： 

        "No”, says he, "I'm too old, b'sides I'm a many sizes too large."-- Dickens: Pickwick Papers (“不”，他说，“我太老了，而且我在许多尺寸上都太大了”。) 

        I don't think you'll see a many such. --  Dickens: Master Humphrey's Clock. (我想你不会见到许多这样的情形。） 

        They go to a many places. (他们要去许多地方。）