I'm finding it increasingly difficult to fill those gaps. The process typically goes like this.

1. Realise I need to learn x, out of interest, necessity, etc.

2. Start reading a book on x, the book assumes I have an understanding on y and z as well, which I don't, so I realize I should learn those first.

3. Buy a book on y or z

4. Repeat step 2, but for whatever I just started reading on.