I think you probably need to read different books as pack theory is a load of bollocks and will not turn your new puppy into a happy sociable dog.
Books re Puppies I would start with:-
Puppy Primer by Patricia McConnell and Brenda Scidmore
Life Skills for puppies by Helen Zulch and Daniel Mills
General book on how dogs learn:-
How dogs learn by Burch and Bailey
Below is advice below from an excellent dog trainer and professional.
Choosing a responsible breeder By Sadie Brunskill
If you have decided that rescuing/adopting or fostering a dog is not for you and you would prefer to buy a puppy from a breeder, please make sure that you are making a responsible choice and are not contributing in any way to the epidemic of unwanted dogs in the UK.
Here is a checklist for you to make sure that you are gaining a happy, healthy family member from a responsible person and some alarm bells that should tell you to be very, very cautious. It is by no means exaustive but, personally, I would not want to buy a puppy from a breeder who does not meet all of these criteria and I would walk away should any of my alarm bells sound.
A good breeder should…
… Allow you to see the mother with the puppies and show you a picture of Dad and his pedigree papers.
ALARM BELL - If mum and dad are in the same house be sure that they have chosen this mating carefully (taking into account both dog’s heritage and health) not just because they happened to acquire two dogs of the same breed and fancied mating them or it happened by "accident".
… Have details of mum and dad’s ancestors going back at least three generations and be able to show that they are free from genetic diseases and conditions. Contact a breed club to find out what tests the breeder should have carried out on mum and dad before the mating.
… Register litters with the Kennel Club. Primarily to ensure that records of all dogs are kept. It is the law that records of all cattle bred and sold in the UK are kept by the government; it should absolutely be the same for dogs. This way close breeding can be avoided and any genetic diseases can be eliminated without dogs needing to suffer from painful conditions like hip dysplasia or epilepsy. If these conditions are not tracked – there is no way to know if/when they are going to crop up; it is pot luck.
ALARM BELL – if the breeder does not register with the Kennel Club and is not able to show you proof that she is breeding from healthy dogs then your puppy could develop a painful or fatal condition and, if owners of other dogs from the litter decide to breed (without knowing what their dog is carrying), these conditions could travel through hundreds of dogs causing unnecessary suffering to both the dogs and their families.
… Rear the puppies in a home environment and follow an early socialisation plan from day one, getting the puppies used to different noises, surfaces, being handed, etc.
ALARM BELL – if your puppy is being kept in a kennel or barn and not in the family home it is unlikely to be getting the best early socialisation. Puppies that are not appropriately socialised before the critical socialisation window closes, at around 12 to 16 weeks, are far more likely to become anxious and aggressive adult dogs. The earlier you can get a puppy used to all of the things he will encounter in his adult life - the happier and more confident the dog will grow up to be.
… Be happy to answer questions about their dogs (most good breeders will relish the opportunity to talk about them!) and they will also have a lot to ask you. They will want to know about your life and insist on visiting your home. Try not to take this personally - good breeders care about their dogs and will take an interest in them for their whole life.
ALARM BELL – If a breeder does not seem interested in you, is happy to let you take the puppy away without seeing your home or getting to know you or gives you a sob story like “this dog will be put to sleep if you do not buy him today” you are dealing with a puppy farmer. Do not buy the puppy. Walk away.
… Compete in breed showing, dog sports or working trials (or be able to tell you of dogs that they have bred who do) to prove that they are fit and healthy examples of their breed with good temperaments or working ability.
ALARM BELL – Even if you are buying a puppy from working dogs, from a farm for example, all of the afore mentioned rules for good breeding practice still apply. You must also be aware of your dog’s particular breed traits and drives and be prepared to give them some sort of job to fulfil them.
… Will not let their pups leave for their new home until somewhere between 8 and 12 weeks.
ALARM BELL – Beware of people making excuses as to why the puppy will be ready earlier than this. It is essential that the litter stay with the mum until 8 weeks to learn bite inhibition and develop social skills.
… Will have you sign a contract or at least have you verbally agree that if for any reason you need to re-home your dog (at any point in his or her life) he is returned to them. Responsible breeders love their dogs. They do not want them to be relinquished into the already-stressed rescue system, passed around or put to sleep.
ALARM BELL – If a breeder is re-homing or selling their dogs (especially ones they have bred from) then it is obvious that they do not take responsibility for their dogs entire lives. No dog is a commodity to a good breeder, they are always a family member.
… Breed their dogs for the love of the breed - to improve the health and fitness of their breed. Not for profit, purely for looks or by “accident”.
ALARM BELL – If a breeder is producing crosses (“designer dogs”) they should still have all relevant health checks done on both parents. It is a common misunderstanding that cross bred dogs or mongrels will be healthier than pedigree dogs. They are just as likely to inherit genetic conditions from both parents. If a breeder who is producing cross breeds or more than one breed is a responsible breeder according to all of the points I have covered in this list, I would be very surprised. You are more likely to be dealing with a puppy farmer or back yard breeder who is cashing in on the latest trend for “designer dogs” and the media-fuelled confusion about pedigrees.
Really wonderful, responsible, caring breeders often have homes lined up for their puppies before they are even conceived and waiting lists for planned litters.
Irresponsible breeders are churning them out at such a rate that you can get one immediately if you are looking to impulse-buy a life-long companion. It really is worth the wait for your perfect puppy; both in terms of their health and temperament as adults and to do your part towards countering the throwaway pet culture of the UK.
Never, ever buy a puppy from a pet shop, online website or buy/swap/sell site, newspaper advert or from someone who did not breed the litter (a puppy dealer).
Great breeders do not need or want to advertise and no responsible breeder would sell their puppies to a middle man.
If you do happen to find yourself in the home or business premises of an irresponsible breeder, please try and think logically - do not buy the puppy.
You may think that you are saving him from this terrible situation or look into those little eyes and believe that you are unable to refuse but you would only be fuelling this unethical trade should you give them your money.
He will only be shortly replaced by another.
Of course I urge all of my clients to rescue or foster because there are so many unwanted dogs in the UK in desperate need of homes, but this is not enough to solve the problem.
We need to look at the bigger picture and where these dogs are coming from. It is not from responsible breeders (who meet all of the conditions I have listed above and more).
It is not useful to tar every person who breeds dogs with the same brush. Although, unfortunately the responsible breeders are in the minority, they do exist.
Of course the dogs in rescue need loving families but we can also stop this epidemic at the source. We need to be logical as well as passionate to make a real difference. If the demand for these irresponsibly-bred dogs stops, eventually so will the supply.