Too big, too slow, too sparse?

We describe a problem that you probably don’t have.

Our astronomer has set out to learn Python, the programming language.  The motivation comes from the fact that there are many programs already written in that language, including a few that he wants to use.  It’s certainly more efficient than writing his own from scratch in any of the languages he knows.

To do this, he bought books and has been reading them, intending to write programs of his own along the way to test his understanding.  The people who can learn on their own from a textbook are a minority, probably a small one; most people would prefer online videos or tutorials.  Well, our astronomer may wind up online, for his experience with Python textbooks has so far been disappointing.

He first bought the sixth edition of a book he remembered skimming some two decades ago.  It must be a successful book, to go to six editions, right?  Well, it is some three or four times the size of the second edition.  The extra length comes from putting in all the details and repeating material, sometimes several times.  After a couple of hundred pages our astronomer was still not ready to do any real coding.  The book really needed a stern editor to impose some discipline; we guess that the success of earlier editions gave the author a misleading idea of how good a writer he was.

So, when our tutor was in a computer shop looking for a laptop repair, he noticed a slimmer Python book and bought it for our astronomer.  This one is a bit better at setting out how to actually do coding.  However, although it advertises itself as aimed at all levels of programmer, it’s actually written for the raw beginner.  It moves very slowly.  Our astronomer is using it, though, skimming material he’s already familiar with.

Choosing, using and especially writing a textbook like these is difficult.  For something like High School mathematics one can make assumptions about the background and ability of one’s audience that are broadly true.  For these sort of side-subjects one cannot, and the author has to decide just who might buy the book.  The reader has to work out for whom the book has actually been written, and how successfully.

For not all textbooks are successful.  Our astronomer still has one on a topic in advanced mathematics that was particularly frustrating.  He wasn’t sure, in several places, whether he was expected to be able to derive a formula, or remember it from a previous class; or whether the author had just pulled it in from somewhere and expected the reader to accept it.  He finally put it down when the author changed his notation from one page to the next without telling anyone.

Reading a textbook is probably not how you learn.  But this account of our astronomer’s difficulties might at least console you that others can be baffled also.