This is a classic logic puzzle often referred to as the "Einstein's Riddle." To solve it, we will organize the information step by step to determine the relationships between the houses, their colors, the nationalities of the occupants, their pets, and what they drink. Here’s how we can approach it:

1. Set up a grid: We can create a table with columns for the house number, color, nationality, drink, and pet.
2. Start with known facts:
   • The Norwegian lives in the first house (clue 10).
   • Milk is drunk in the middle house (clue 9).
   • The green house is immediately to the right of the ivory house (clue 6).
3. Fill in the table with what we know:
   • House 1: Norwegian, ?, ?, ?
   • House 2: ?, ?, ?, ?
   • House 3: ?, ?, Milk, ?
   • House 4: ?, ?, ?, ?
   • House 5: ?, ?, ?, ?
4. Use clues to deduce more:
   • Since the Norwegian lives next to the blue house (clue 15), House 2 must be blue.
   • Now we can update our table:
     • House 1: Norwegian, ?, ?, ?
     • House 2: ?, Blue, ?, ?
     • House 3: ?, ?, Milk, ?
     • House 4: ?, ?, ?, ?
     • House 5: ?, ?, ?, ?
5. Continue filling in based on clues:
   • The green house drinks coffee (clue 4) and must be to the right of the ivory house. Therefore, Houses 3 and 4 must be green and ivory, respectively.
   • Now the table looks like this:
     • House 1: Norwegian, ?, ?, ?
     • House 2: ?, Blue, ?, ?
     • House 3: ?, Green, Milk, Coffee
     • House 4: ?, Ivory, ?, ?
     • House 5: ?, ?, ?, ?
6. Continue deducing:
   • The Englishman lives in the red house (clue 2) which must be House 5 since House 3 is green and House 4 is ivory. Therefore, House 1 must be yellow (clue 8). Now we can fill in more:
     • House 1: Norwegian, Yellow, ?, ?
     • House 2: ?, Blue, ?, ?
     • House 3: ?, Green, Milk, Coffee
     • House 4: ?, Ivory, ?, ?
     • House 5: Englishman, Red, ?, ?