I confirm the best option is the one proposed by Peter and voretaq7
However [personal opinion], I think it won't fulfill three main requirements in spotting :
- precision
- contains almost every plane
- portable
I have the french version of that book (because I'm french speaking)
Precision
Precision is what you need to spot the differences between an A318 and an A319 (or a 737-600 and a 737-700) for example. Using the number of passenger windows count/number of exits. Knowing for example a 737-300 can have winglets and no cockpit eyebrows since a dozen years avoids confusion with a 737-700 by looking at the other differences (engines, tail height/size, wingspan, wingroot, flaps slats, spoilers, no winglets wingtip, stabilizers, etc.)
Details you don't have in that book, but you rather gather by experience and curiosity elsewhere.
The book just provide you - per featured model -
- one arbitrary picture of the plane (sometimes granny)
- one 3-views, mostly left, top (or bottom) and front.
- a brief historic description
- a non exhaustive list of most common produced versions in bold with one specific information that makes this version different from others (mostly the operation type like "cargo version", or increased MTOW..)
- a non exhaustive list of weapons for military aircraft, role and operators if a few countries operate the model.
- a resumee of its caracteristics (seats, payload, speed, range)
- its dimensions (wingspan, overall length, height)
- and a brief way to describe the general looking of the plane (hight/low mounted wings, engines location, model and manufacturer, number of fans for propellers, stabilizers location, one very noticeable caracteristics if any like domes, fuel pods, cargo pod..)
The arbitrary picture can help recognising the aircraft, but seen from other directions, it doesn't help much.
By experience, 3 views doesn't well represent 3D or field depth, as every component is flattened on a drawing (I'm modeling 3D airplanes/Aircraft profiles) Note : some drawings in the book contains minor errors.
The historic description is of no real use in spotting.
Today, model versions are not really relevant, since most aircraft are customizable (mainly commercial aviation) Military aircraft are usually multirole. This kind of information is only useful for someone actually operating/working on the model (ie a pilot or engineer or reproducing the model (3D/scale model)) Weapons loadings greatly vary per mission.
The general looking description is too broad/vague to get a perfect match. Its purpose is more to class a given model in a group of similar models to narrow the identification process to one or two dozens of aircraft than precisely describe the model.
Every plane ?
Impossible ! The book contains commercial, military, fixed wings, tiltrotor, general aviation, utility... It doesn't even contain soaring light weight planes. And you already have several hundreds models.
Some models has to be merged to fit in a single page, like the 737NGs, A330s, B767/777, ERJ17x/19x... (And I'm not talking for military ones)
Of course, most common models are covered, but if you're spotting a Bizjet landing in Heathrow it could take a while before you can clearly confirme it's a Gulfstream V rather than a Gulfstream IV. Worse, when you're looking for single engine propeller. Even worse if the aircraft you're spotting isn't featured in the book, then you could assume it's model X while it isn't.
Portable ?
To have every planes and be precise, you'll end with the encyclopedic version which is actually two very large books with hundreds of pages. You'll look weird bringing those with you while spotting, and it will take even longer to parse it to find your model...
ie : don't !
What I mean is, you can't have enough info in a book that will really help you identify any airplane on first sight.
Dont mistaken me - note for others aswell :
This book is an extremely valuable one and is worth its price, really !
I'm enjoying it very much and has proven useful countless times for me.
...but not in spotting !
This book is the best option I know.. as a book.
I'm just answering the question "Looking for the most accurate planespotter book" and this book is the one that approximates well the OP's requirements.
But honestly, I think no book will ever fit your needs, unless it's an application on a tablet you can do queries, and contains a huge database of planes in the world with enough informations. I'm not aware of such any application (because I don't have/use/like tablets)
Otherwise :
If you have time to read a book, I would rather suggest to spend that time to visit some spotting sites like Airliners.net or Planespotters.net, forums like Airlinercafe.com aswell as manufacturer's websites, looking for technical documents in PDF format.
Identifying a plane at first glimpse is not a matter of having a tool doing it for you. It's more beeing used look at that plane from different spotting angles, noticing the bits that makes it different from other models, and memorizing that.
And, there are some useful informations you can get by not reading a book but, rather crawling the web (unless you're a collectionneur that has bought thousands books, one dedicated to a particular model) For example, I always had the feeling there was something weird between the Boeing 707(-320) fuselage and the 727s/737s ones. But I couldn't find out what until I read somwhere that "since 727s and 737s are rather short/medium ranges models, it wasn't required to have as much space in the cargo belly. Boeing decided to shrink the lower part of the fuselage." That's why 707 noses looks "sharper" than 727/737s...
PS : each page of the book is rather filled with datas. You don't have much space to add notes, but you can mark a cross though that means you've spotted the plane :) But it would only apply to the (few) pages of the models flying in your region (unless you're a serial traveller and international spotter...)
The book doesn't have IATA/ICAO listing of each airplane. It's rather intended to lambda aviation enthusiasts than the few looking for such specific piece of information.