One of my favorite crochet books is My Crochet Doll by Isabelle Kessedjian. I found it while browsing at Barnes and Noble and thought the patterns were super cute. The problem that I had was that this book is written in UK terminology so I had transpose the stitch terminology (for example, double crochet in the UK is single crochet in the US). Using the book I have made three dolls so far. The first one was a present for my younger sister's 8th birthday, along with the Little Red Riding Hood outfit and a little purple fabric quilt and pillow.
The first one took me 3 months because of the hair. I attached the strands one by one so it took forever. I used a G/4.25mm hook with Red Heart Super Saver yarn in Buff for the body color and Caron Simply Soft in Black for the hair.
Then I decided to make a second doll with crochet thread and a 12/1.00mm hook just to see if it was possible to do. It turned out to be far trickier. It took me 2-3 weeks. The hardest part was sewing the limbs together, especially sewing the scalp to the head. It was so hard I had to use a magnifying lamp. I wish I could accurately portray in words and photos how much time, skill and coordination it took. I mean, you can barely even feel the hook, much less see it. Most of it was done by feeling the hook and stitches. I accidentally dropped a few rounds but it came out better for having done so.
(Just for size comparison, the big doll is 14 inches and the small doll is 4 inches.)
For the third doll I used the same hook and skin color as the first doll but used Red Heart Super Saver in Pale Yellow for the hair (with the same skein as before for the body.) This time I knew what I was doing so it only took me a week. The hair and scalp only took 5 or 6 hours to do instead of taking 3 months because I changed my technique. (The book gives no instruction on how to actually do the hair.) This time instead of attaching the hair strands one by one with a needle, I wound the yarn around a piece of cardboard and attached the hair strands 2 or 3 at a time with a smaller crochet hook.