When I think back to the days when I started birdwatching in the 1970s, there were relatively few books to help you decide how to watch birds. You really relied on meeting others in order to "learn the ropes". Had this book been available back then I think that the ability of me and my teenage friends to understand the hobby would have accelerated at least four times faster than it did.
The first section (Getting Started) uses eight clear steps to teach us about the physical adaptations of birds including plumage, structure, wings, feet, beaks and so on. It also explains how and why birds sing, and why some birds don't have a song. The next part (Getting Closer) introduces the tools of the trade - optical equipment, clothing and books. It also tells you how to interpret distribution maps and how to keep your own useful notes. There is a general introduction to the various bird groups. The third chapter (Finding the Birds) runs through the main habitat types. Basic behaviour and biology is covered in another section (Understanding Birds) and another (Helping Birds) particularly covers bird feeding and nestboxes. The closing chapter provides all the links you need to take your hobby from where it is to wherever you want it to be - whether that is joining a club, volunteering to clear scrub, taking part in surveys, ringing or taking photographs. There is a checklist of 270 regularly-occurring British birds, although it would have been helpful to indicate the abundance of each and the likely seasons that they will occur.
Of course you can't learn fieldcraft from a book, but as a complete novice if you were locked up and forced to read this book from cover to cover I think that on your release you could convince many birdwatchers that you had been an active birder for many years!