Is the below schema defined correctly or does writing need to be
writing: [Schema.Types.Mixed] or writing: [{}]? 
That is, if you have an array of dictionaries -- [{},{},{}] -- one can't predefine the internal structure unless you create another schema and embed it. Is that the right interpretation of the docs?
http://mongoosejs.com/docs/schematypes.html
var blogSchema = new mongoose.Schema({
  title:  String,
  writing: [{
        post: String,
        two: Number,
        three : Number,
        four  : String,
        five : [{  a: String,
                    b : String,
                    c  : String,
                    d: String,
                    e: { type: Date, default: Date.now }, 
                }]
  }],
});
Thanks.
				
				That schema is fine.  Defining an object within an array schema element is implicitly treated as its own Schema object.  As such they'll have their own _id field, but you can disable that by explicitly defining the schema with the _id option disabled:
var blogSchema = new mongoose.Schema({
    title: String,
    writing: [new Schema({
        post: String,
        two: Number,
        three : Number,
        four  : String,
        five : [new Schema({ 
            a: String,
            b: String,
            c: String,
            d: String,
            e: { type: Date, default: Date.now }, 
        }, {_id: false})]
    }, {_id: false})],
});