Experienced inventors often say that the conception, prototyping and the obtaining of a patent are relatively easy processes compared with the successful manufacturing and marketing of an invention. This is not due to a shortage of manufacturers. Today there are literally millions of factories worldwide.

How does one locate ones that can make your product? As the old Chinese proverb says, a long journey begins with one simple step - in this case, a trip to your local library. Do not assume this is a grade-school approach. Very high-priced professional searches start out with this simple step.

For purposes of this discussion, we will restrict our search process to non-computer searching. Surprisingly there are still some advantages to old-fashioned book searching - and this experience will aid you in later computer searching.

If there's one best starting point, it is the Thomas Register of American Manufacturers and Service. This massive 30-volume set of books occupies 8 feet of shelf space. It is divided into 3 main sections: a 20-volume (40,207 pages!) Products and Services Section; a 2-volume Company Profile Section which lists company names, addresses, phone and fax numbers and, in many cases, a list of products the company manufactures; a Catalog File section (14,077 pages).

Entries run from Abacus Manufacturers (3) to Zoo Equipment and Supplies (30). In addition, a 532-page section lists many common American trade names. The Register's main index fills 170 pages. All of this is revised and published annually.

Let's take some examples of how you might use the Thomas Register. Suppose during your next backyard picnic, it occurs to you that charcoal briquettes could be improved in some way. A quick check of your local library's "Thomas" would reveal 16 manufacturers in 11 states. Or while fishing, you decide fish hooks need improving. Again, a quick look will locate 8 manufacturers. If you already have an item and found that stores require blister packaging, a quick look will locate (under Blister Packaging Service - Contract for example) some 60 firms in Ohio and another 25 in Michigan.

While the "Thomas" is a good starting point, there are many other directories available to you. One example is the Harris directories published by Harris Info Source International. They publish individual state directories annually for most states, including Illinois, Indiana, Kentucky, Michigan, Ohio, Pennsylvania, Virginia and West Virginia.

The "Harris" has 4 main sections listing manufacturers by City, by SIC (Standard Industrial Classification), by Company Name, and by Product. The listings provide you with the company's name, phone and fax numbers, name of their executives, number of employees, the year the firm was established, ownership, square feet of plant, estimated sales and SIC code.

One way to focus your search is to identify how your product is classified. A 705-page book put out by the (federal) Office of Management and Budget (OMB) will enable you to do just that. It is called the Standard Industrial Classification Manual. It divides all of the nation's economy into 99 major groups - 01 through 99. By adding digits, if further divides so that your product will be found in at least one of 9,999 divisions. For example, that charcoal briquette you improved would fall into Major Group 24 (Lumber and Wood Products) - and then into Industry Group 249 (Misc Wood Products) - and then into Industry Number 2499 (Wood Products Not Elsewhere Classified).

However, note that even with 4 digits, briquettes (2499) share their classification number (SIC #) with 59 other products - from wood applicators to wood oars. But at the same time, once you know your product's SIC number, you will not be asking an iron foundry if they make fish hooks.

How to quiz your potential manufacturer is another subject altogether. But do remember a basic rule - unless you have obtained your patent, do not reveal how your device works, only what it achieves.