Step 1 Place the roast, bone side up, on a cutting board and locate the rubbery seams between the vertebrae. Crack through each one by easing the blade of a heavy cleaver or the bolster of a heavy chef's knife into each joint and then tapping firmly with a rubber mallet (or a hammer wrapped in a towel). It may take a few taps to go all the way through the seam and joint, but take care not to cut deeply into the meat itself. The blade of your knife ought to sink no more than 1 1/2 inches into the seam.
Step 2 Flip the roast over and trim away all but 1/4 -inch-thick layer of fat. Begin boning the loin, starting with the thin layer of meat and fat near the end of the rib bones. Resting the tip of your knife flat against the curved rack of bones, make a series of smooth cuts between the loin and bones until you reach the "elbow" of each rib bone. Leave the loin attached to the other angle of the "elbow," so you can open and close the roast like a book.
Step 3Season the whole roast, including the rack of bones, literally inside and out with salt (we use about 1 tablespoon sea salt for 3 pounds of roast); target the thickest sections most heavily, and the two end faces of the loin most lightly. Roughly chop the garlic, then crush in a mortar. Smear on the inside face of the loin. Slightly crush the fennel and coriander seeds. Scatter about two-thirds of them on the inside of the loin and the facing bones, then close the loin back up and sprinkle the remainder evenly over all of the other surfaces.
Step 4Truss the roast, looping and knotting a string between every two ribs. Cover loosely and refrigerate. (Remove the pork from the refrigerator about 3 hours before roasting.)
Step 5Preheat the oven to 400 degrees.
Step 6I usually take the temperature of the roast just before cooking it, looking for 50 degrees at the center of the thickest section. Stand the roast in a shallow roasting pan or in a heavy rimmed baking sheet not much larger than the meat. Place in the center of the oven. For a juicy roast that is cooked through, but with a faintly rosy cast, roast to 135 degrees. (If the eye of your roast is smaller than 4 inches across, cook it to about 140 degrees; it will stop cooking more abruptly when you remove it from the oven.) Start taking its temperature at about 45 minutes, and allow between 1 and 1 1/2 hours for a 4-pound roast. Turn the roast or adjust rack height if it is browning very unevenly.
Step 7Set the roast on a platter, tent loosely with foil and leave to rest in a warm, protected spot for about 20 minutes, then take the temperature again. Like any roast, it will continue to cook as it rests, but the rack of bones retains heat particularly well, so the temperature should climb to about 160 degrees. The meat will be cooked through but still moist.
Step 8Pour any fat from the roasting pan, then moisten it with the pork stock, the chicken stock or the water and wine, to capture