This is correct.

When you refer to them in the book as "troughs of low pressure" (page 357) is this intentional? Have I correctly understood that troughs are areas of lower contours (but higher pressures) which normally originate from the poleward direction?

You understand this correctly–what I was referring to on 357 is an area of low pressure–not low isoheights–another way to say this would be that what you need to watch out for are 500mb areas of high isoheights which equate to low pressure. When this occurs over a surface high the upper level weather can penetrate through the weak surface high to create a tropical storm.

Secondly, on page 338 is a diagram showing the typical direction of storm tracks. It appears that most storms in the northern hemisphere start by heading west before heading in a northerly direction. In the Southern Hemisphere the direction of travel is just the opposite–on a primarily southerly course (southwest to southeast). In the chapter on Hurricane Avoidance, the diagrams (pages 398, 403, 409, 412) seem to indicate that the storms can track opposite to that shown in the diagram mentioned above (i.e. northerly in the southern hemisphere). Am I taking the "direction of travel" arrows too literally when they show that these storms sometimes go opposite to their typical paths?

The direction of travel is a function of the local steering currents. For example, the stuff in the Atlantic/Caribbean typically goes towards the west because it is being carried along by the circulation on the bottom side of the Atlantic High. However, when these storms get to the western edge of the high, which then curves northward, the storms move with the high’s circulation pattern to the north.

In the South Pacific, during the summer, you can see systems moving to the east as the typical high pressure flow is disrupted, or moved quite far to the south. In the chart in the book, most of the South Pacific arrows are probably being influenced by the counterclockwise high pressure circulation in that part of the world.

So, the main issue is to watch the local conditions to see what the direction of circulation is (typically around a surface high) and how thick that circulation is–if it is thin, i.e. not real strong, there is no telling what the tropical storm will do.

Another thing to consider is that some of these tropical storms will have a major impact on their surroundings, and create their own environment–this typically happens when the steering currents are weak, not well developed, not thick enough, or the tropical storm becomes really large.

Isn’t it fun having all these hard and fast rules which always apply without exception!