This is a great book, I based my Vietnam cycling trip on the North by Northwest route described.
There were a couple of small drawbacks though, the book isn't entirely comprehensive and the maps could be better, however the altitude maps were crucial and the directions were certainly sufficient.
There are also some very useful recommendations. The only area I usually disagreed with was the restaurant recommendation section. The authours tended to select 'westernised' establishments, whereas I prefer to mix in with the locals to get the most authentic food, but I guess this is a matter of personal taste.
So overall a very useful book that made for a great holiday, with only a few minor points to be aware of.
This is a great book to get you enthusiastic when reading at home before you go, but when out on the road with it, it is a different story. I think it is summed up by looking at the main Vietnam Lonely Planet Guide, they say don't cycle on highway 1 as it is too busy and dangerous. Open the Lonely Planet Cycling Guide and you will see it has 2 long routes that follow this road. We tried it and it was awful. Definately don't ride the Maekong Delta Meander route it is dangerous and not enjoyable. Maybe some of the other routes are better. The cycling Australia book we have also used and those routes were quite good. As for the rest of the general issues with the book. -The maps are too small scale to find things on. Often using 1 map for 2 or 3 days cycling. -The route notes often miss things like many major junctions and turnings. -We got lost when the text said go SW and it should have said NW. -It is not spiral bound and therefore hard to use on a bike. -The maps are not orientated north south.